Lymphomatoid Papulosis With T-cell Receptor-Gamma Delta Expression: A Clinicopathologic Case-series of 26 Patients of an Underrecognized Immunophenotypic Variant of Lymphomatoid Papulosis.

Lymphomatoid papulosis (LyP) has several histopathologic presentations. LyP featuring gamma-delta (γδ) T-cell receptor expression may masquerade as and may be misdiagnosed as aggressive cutaneous T-cell lymphoma, particularly primary cutaneous γδ T-cell lymphoma (PCGDTL) or γδ mycosis fungoides. We performed a clinicopathologic analysis of the largest series of LyP featuring γδ T-cell expression. We identified 26 patients with a diagnosis of LyP with γδ T cells from our institutions, as well as through a comprehensive review of the literature, and characterized these cases. Most cases were treated with topical steroids or not treated at all. The majority of cases showed a CD4 - CD8 + phenotype and featured at least one cytotoxic marker. Histopathologic features included an intraepidermal or dermal infiltrate with large cells and frequent angiotropism. One case was initially misdiagnosed as PCGDTL, requiring further therapy. Our case series, the largest international cohort of γδ T cell predominant LyP cases, confirms marked clinicopathologic heterogeneity that may contribute to misdiagnosis, reasserting the need to identify classic clinical features, CD30 + T-cell components, and markers of cytotoxicity when dealing with this differential diagnosis. A limitation of this study includes somewhat limited follow-up, histologic, and immunophenotypic information for some cases.

Prevention of incisional hernia after kidney transplantation: study protocol for a randomized controlled trial.

BACKGROUND: Incisional hernia is a common complication after kidney transplantation with an incidence of 1.6-18%. Concerning non-transplant patients, a recently published meta-analysis describes a reduction of the incidence of incisional hernia of up to 85% due to prophylactic mesh replacement in elective, midline laparotomy. The aim of our study is to show a reduction of the incidence of incisional hernia after kidney transplantation with minimal risk for complication. METHODS/DESIGN: This is a blinded, randomized controlled trial comparing time to incisional hernia over a period of 24 months between patients undergoing kidney transplantation and standardized abdominal closure with or without prophylactic placement of ProGrip™ (Medtronic, Fridley, MN, USA) mesh in an onlay position. As we believe that the mesh intervention is superior to the standard procedure in reducing the incidence of hernia, this is a superiority trial. DISCUSSION: The high risk for developing incisional hernia following kidney transplantation might be reduced by prophylactic mesh placement. ProGrip™ mesh features polylactic acid (PLA) microgrips that provide immediate, strong and uniform fixation. The use of this mesh combines the effectiveness demonstrated by the macropore propylene meshes in the treatment of incisional hernias, a high simplicity of use provided by its capacity for self-fixation that does not increase significantly surgery time, and safety. TRIAL REGISTRATION: ClinicalTrials.gov NCT04794582. Registered on 08 March 2021. Protocol version 2.0. (02-18-2021).

Poorly Differentiated Scrotal Carcinoma With Apocrine Immunophenotype.

ABSTRACT: Cutaneous carcinoma of the scrotum is rare with the most common type being squamous cell carcinoma. Here, we report 6 cases of poorly differentiated carcinoma with apocrine immunophenotype. Mean age at presentation was 68 years (range: 31-91 years). Clinical presentation included eczematous rash over mass, scrotal cyst, ulcerated mass, and mass. Tumor size ranged from 1.2 to 5.5 cm (average 2.5 cm). The tumors were solid with involvement of the dermis/hypodermis and composed of cords and nests of eosinophilic cells displaying nuclei with prominent nucleoli and surrounded by desmoplastic stroma. Focal squamous differentiation was evident in one case (17%). An intraductal component was seen in one case (17%). Pagetoid spread in the epidermis was seen in 3 cases. There was no morphologic evidence of apocrine differentiation. By immunohistochemistry, the tumor cells were positive for GCDFP-15 (n = 6/6), GATA3 (n = 6/6), CK7 (n = 5/5), AR (n = 4/4), and mammaglobin (n = 3/5). Five (83%) patients had metastases at diagnosis. Treatment included wide local excisions and inguinal lymph node dissection, followed by chemotherapy (gemcitabine, carboplatin; n = 3), trastuzumab/Lupron (n = 1), tamoxifen/Arimidex (n = 1), and radiotherapy (n = 1). Two patients (40%) were dead of disease, less than 2 years from diagnosis. Four patients developed metastases to lymph nodes, liver, bones, and lungs. Molecular analysis (n = 2) detected a HER-2 mutation in one and microsatellite instability in another. Although the presence of an intraepidermal pagetoid component could hint toward the diagnosis of invasive extramammary Paget disease, tumors without an intraepidermal component could be diagnostically challenging given the lack of morphologic evidence of apocrine differentiation.

How has the COVID-19 pandemic influenced prostate cancer?-a tertiary single-centre analysis of oncological results, diagnosis and treatment times.

Background: The coronavirus disease 2019 (COVID-19) pandemic has affected care for diseases like cancer. The aim was to evaluate the impact of COVID-19 on waiting times for diagnosis and treatment of prostate cancer (PC), as well as the possible effect on the treatment results in PC patients undergoing radical prostatectomy. Methods: We compared the results of 497 patients who underwent biopsy prior to the COVID-19 pandemic (1 January-31 December 2019) with those of 290 patients biopsied during the COVID-19 pandemic (1 January-31 December 2020). Demographic data, tumour characteristics, type of treatment and diagnosis times were comparable. Prostate specific antigen (PSA) levels were recorded at consultation prior to biopsy and after treatment. Mann-Whitney and chi-square tests were used to compare continuous variables and percentages, respectively. Results: In 2020, there were fewer urology consultations (35,160 vs. 40,225 in 2019). The median PSA in 2020 was significantly higher (14.3 vs. 9.9 ng/dL in 2019). In 2019, 53.1% (N=264) of the biopsies were positive for cancer vs. 47.2% (N=137) in 2020 (P=0.104). In 2020, more patients presented with metastatic disease (7.3% vs. 1.9%, P=0.009). Also, in 2020 there was a longer waiting time for prostate biopsy (42.1 vs. 35.3 days in 2019, P=0.019). A total of 132 patients underwent laparoscopic radical prostatectomy (LARP). The median time until surgery was similar in both years (71.9 vs. 58.29 days). During 2020, a higher percentage of patients had ISUP grade 4 in the surgical specimen (34.3% vs. 17.5%, P=0.07). Furthermore, a higher percentage of aggressive (pT3) tumours were diagnosed (37.2% vs. 27.2%, P=0.08), and the percentage of patients with involvement of surgical margins was also higher (48.6% vs. 29.3%, P=0.027). There were no differences between the groups in terms of biochemical recurrence or persistent PSA at one year (P=0.711). Conclusions: Delayed biopsy during the COVID-19 period did not appear to adversely impact biopsy results. Patients biopsied in 2020 had higher PSA, possibly due to proper triaging. A higher rate of adverse pathology outcomes was observed in patients undergoing radical prostatectomy during the pandemic, probably due to understaging of the biopsy. This study serves to raise awareness of the risk of deterioration of care of PC patients due to possible underdiagnosis.

Polysilicon-chromium-gold intracellular chips for multi-functional biomedical applications.

The development of micro- and nanosystems for their use in biomedicine is a continuously growing field. One of the major goals of such platforms is to combine multiple functions in a single entity. However, achieving the design of an efficient and safe micro- or nanoplatform has shown to be strongly influenced by its interaction with the biological systems, where particle features or cell types play a critical role. In this work, the feasibility of using multi-material pSi-Cr-Au intracellular chips (MMICCs) for multifunctional applications by characterizing their interactions with two different cell lines, one tumorigenic and one non-tumorigenic, in terms of biocompatibility, internalization and intracellular fate, has been explored. Moreover, the impact of MMICCs on the induction of an inflammatory response has been assessed by evaluating TNFα, IL1b, IL6, and IL10 human inflammatory cytokines secretion by macrophages. Results show that MMICCs are biocompatible and their internalization efficiency is strongly dependent on the cell type. Finally as a proof-of-concept, MMICCs have been dually functionalized with transferrin and pHrodo™ Red, SE to target cancer cells and detect intracellular pH, respectively. In conclusion, MMICCs can be used as multi-functional devices due to their high biocompatibility, non-inflammatory properties and the ability of developing multiple functions.

Hydroa vacciniforme-like cutaneous T-cell lymphoma: clinicopathologic and immunohistochemical study of 12 cases.

BACKGROUND: Hydroa vacciniforme (HV)-like lymphoma (HVL) is a rare and aggressive cutaneous T-cell lymphoma occurring mainly in children in Latin America and Asia. Chronic latent Epstein-Barr virus infection has been associated with both HV and HVL. OBJECTIVE: We sought to evaluate the clinical presentation and histopathology of this rare cutaneous T-cell lymphoma. METHODS: We reviewed the clinical, morphologic, and immunophenotypical features in 12 cases of HVL from Bolivia. RESULTS: All 12 patients had skin lesions in both sun-exposed and nonsun-exposed areas, including edema, blistering, ulceration, and scarring, with a slowly progressive relapsing course. All 12 patients presented with systemic symptoms and showed a characteristic swelling of the nose and lips, and periorbital edema. Eight patients died an average of 5.3 months after initial diagnosis. Four patients remained alive with persistent disease. Histopathologic examination showed an atypical lymphocytic infiltrate with angiotropism and angiocentricity. The immunophenotype showed a cytotoxic T-cell (CD8(+)) profile. All cases were associated with Epstein-Barr virus infection and differed clinically from other forms of cutaneous T-cell lymphoma. LIMITATIONS: Only a limited number of cases were studied. CONCLUSIONS: This study confirms that HVL is a highly aggressive lymphoma, although some patients have a more indolent, chronic course.

Atypical melanocytic lesions of the thigh with spitzoid and dysplastic features: a clinicopathologic study of 29 cases.

Melanocytic nevi in certain anatomic locations can display unusual histopathologic features potentially creating diagnostic uncertainty. Benign melanocytic nevi in sites such as acral, genital, and flexural areas may show unusual architecture and cytologic atypia, which can mimic dysplastic nevi and, sometimes, melanoma. Twenty-nine benign melanocytic skin lesions were identified in the thigh of 26 women and 3 men who showed atypical histologic features, including both dysplastic and spitzoid features. All lesions measured less than 1 cm in diameter. Eighteen cases showed features of compound nevi, and 11 were junctional. In all cases, the lesions displayed spitzoid features including large epithelioid and/or spindle cells, some melanocytes with ganglion-like cytomorphology, and focal suprabasilar upward migration. All cases showed dysplastic features. Clinical follow-up was available in 26 patients; no recurrences or metastases were observed. The demographic features and the anatomical sites of these melanocytic nevi appear to be reproducible, and in the assessment of histologically difficult cases, these data are helpful. It is our opinion that the malignant potential of these lesions with hybrid patterns (spitzoid/dysplastic) has yet to be determined, and although we favor these lesions to be benign, longer follow-up may yield a more complete understanding of their biologic potential.

Orbital inflammation with IgG4-positive plasma cells: manifestation of IgG4 systemic disease.

OBJECTIVE: To describe clinical, radiographic, and morphologic findings in patients with IgG4-positive cells present on orbital biopsy specimens. DESIGN: Retrospective review (from January 1, 1993, through December 31, 2006) of patients with orbital biopsy specimens that excluded lymphoma; comparison of patients with and without IgG4-positive cells on immunostaining. RESULTS: Of 21 patients, 11 had increased IgG4-positive cells (defined as >10 cells on biopsy). Symptoms included eyelid or periocular swelling (8 patients) or proptosis (3 patients), with bilateral involvement in 6 patients. Computed tomographic imaging displayed lacrimal gland mass in 10 patients; 6 patients had lesions in other organs. Two patients had increased serum IgG4 levels. In 10 patients without IgG4-positive cells (≤10 cells on biopsy), 6 had proptosis, 1 had eyelid swelling, 2 had eyelid mass, and 1 had diplopia, all unilateral. None had systemic symptoms. Patients with IgG4-positive cells had longer symptom duration, and their biopsy specimens showed more background fibrosis, lymphoid hyperplasia, plasma cells, and eosinophils. CONCLUSIONS: The clinical appearance, high incidence of bilateral disease, association with lesions in other organs, and increased IgG4 serum levels in some patients-with an increased number of IgG4-positive cells in the biopsy specimen, which shows more background fibrosis, lymphoid hyperplasia, plasma cells, and eosinophils-indicate that these patients have an orbital manifestation of IgG4-associated systemic disease.

Sharp high-aspect-ratio AFM tips fabricated by a combination of deep reactive ion etching and focused ion beam techniques.

The shape and dimensions of an atomic force microscope tip are crucial factors to obtain high resolution images at the nanoscale. When measuring samples with narrow trenches, inclined sidewalls near 90 degrees or nanoscaled structures, standard silicon atomic force microscopy (AFM) tips do not provide satisfactory results. We have combined deep reactive ion etching (DRIE) and focused ion beam (FIB) lithography techniques in order to produce probes with sharp rocket-shaped silicon AFM tips for high resolution imaging. The cantilevers were shaped and the bulk micromachining was performed using the same DRIE equipment. To improve the tip aspect ratio we used FIB nanolithography technique. The tips were tested on narrow silicon trenches and over biological samples showing a better resolution when compared with standard AFM tips, which enables nanocharacterization and nanometrology of high-aspect-ratio structures and nanoscaled biological elements to be completed, and provides an alternative to commercial high aspect ratio AFM tips.

Intracellular polysilicon barcodes for cell tracking.

During the past decade, diverse types of barcode have been designed in order to track living cells in vivo or in vitro, but none of them offer the possibility to follow an individual cell up to ten or more days. Using silicon microtechnologies a barcode sufficiently small to be introduced into a cell, yet visible and readily identifiable under an optical microscope, is designed. Cultured human macrophages are able to engulf the barcodes due to their phagocytic ability and their viability is not affected. The utility of the barcodes for cell tracking is demonstrated by following individual cells for up to ten days in culture and recording their locomotion. Interestingly, silicon microtechnology allows the mass production of reproducible codes at low cost with small features (bits) in the micrometer range that are additionally biocompatible.

Immunohistochemical expression of S100A6 in cellular neurothekeoma: clinicopathologic and immunohistochemical analysis of 31 cases.

Neurothekeoma is a term introduced by Gallager and Helwig describing a superficial tumor of purported nerve sheath derivation, with cellular and myxoid types. Recently, it has been suggested that the cellular type does not have nerve sheath differentiation. This subtype represents an uncommon neoplasm and sometimes can be problematic to diagnose because it can be easily mistaken for melanoma. We studied the immunohistochemical features of 31 cases of cellular neurothekeomas to evaluate their immunoprofile. Immunohistochemical studies were performed in all 31 cases with formalin-fixed paraffin-embedded tissue sections with antibodies against S100 protein, S100A6, and melanoma antigen recognized by T-cells (MART-1). In addition, 8 cases were evaluated for HMB-45 antigen, keratin (with a pankeratin cocktail), epithelial membrane (EMA), and smooth muscle antigen (SMA). The lesions were from 8 men and 23 women aged 6-64 years (mean 35 years). Four tumors were located on the nose; 4 scalp; 4 finger; 3 thigh; 2 shoulder; 2 wrist; 2 hand; and 1 each on pelvis, cheek, toe, chest, eyebrow, forearm, penis, axilla, mouth, and leg. All tumors were positive for S100A6 (100%) and negative for cytokeratin, HMB-45 antigen, MART-1, and EMA (100%); 29 cases were negative for S100 protein (93.5%; the 2 positive cases had only scattered cells labeled), and only 2 cases were focally positive for SMA (7.5%). Therefore, the combination of strong immunoreactivity for S100A6, in nested dermal spindle cell proliferations, and lack of S100 protein or keratin, supports a diagnosis of cellular neurothekeoma.

Unusual cutaneous manifestations of B-cell chronic lymphocytic leukemia.

BACKGROUND: B-cell chronic lymphocytic leukemia (B-CLL) is a low-grade lymphoproliferative disorder with characteristic histomorphologic features and an identifiable immunophenotype. The skin can be involved in the context of known disease, but cutaneous signs are rarely the presenting findings. OBJECTIVE: Evaluation of unusual clinical cutaneous presentations of B-CLL. METHODS: We conducted a retrospective case series analysis of 3 patients with unusual cutaneous clinicopathologic presentations of B-cell chronic lymphocytic leukemia, including erythematous plaques, angiomatosis/telangiectasia, and erosive skin changes, respectively, without a previous clinical history of chronic lymphocytic lymphoma. Main outcome measures were clinical cutaneous presentations and histopathologic results in the diagnosis of underlying disease. RESULTS: In the 3 cases, lesion locations were the lower cheek, lower extremity, and penis (groin region). Histomorphologic testing showed mild to dense perivascular and periadnexal lymphoid aggregates throughout the dermis and extending into the panniculus, consistent with B-CLL. The diagnosis was confirmed with immunohistochemical studies that showed coexpression of CD5 and CD20 in the neoplastic lymphocytic infiltrate. LIMITATIONS: None. CONCLUSION: Cutaneous manifestations are an uncommon presentation of subclinical B-CLL. Cutaneous changes were the presenting features of underlying lymphoma in all 3 cases, highlighting the importance of maintaining a high index of suspicion for a lymphoproliferative process in cases with unusual or atypical clinicopathologic features. Additional investigations into the behavior of B-CLL in the skin may elucidate further the evolution of cutaneous lesions in this disease.

Serous cystadenoma of the pancreas: clinical and pathological features in 33 patients.

AIM: To report the clinicopathological features of patients with serous cystadenomas of the pancreas. METHODS: Thirty-three cases of serous cystadenoma diagnosed between 1977 and 2006 were retrieved from the files of the Ohio State University Medical Center. Clinical data and microscopic slides were reviewed. RESULTS: The patients included 27 women and 6 men with an age range of 38-83 (mean 64.3) years. The clinical presentation included 13 patients with abdominal pain and 8 patients with abdominal mass; 9 tumors were found incidentally. Abdominal CT scans in 25 patients were interpreted as suspicious for carcinoma in 8 (32%), suspicious for serous cystadenoma in 8, neoplasm not otherwise specified in 8, and suspicious for a pseudocyst in 1. Only 7 patients underwent a preoperative biopsy, and 5 of these were diagnosed as having a serous cystadenoma. All but 2 of the patients underwent surgical resection of the tumor. The serous cystadenomas varied in size from 1.0 to up to 13 cm in maximum dimension, and all but one had a multicystic appearance. Of the 33 serous cystadenomas, 20 (61%) were located in the pancreatic tail, 4 (12%) in the pancreatic body, 4 in the pancreatic body and tail, and 5 (15%) in the head of the pancreas. Follow-up in 17 patients (median 3 years, range from 1 month to 11 years) showed no recurrence of serous cystadenomas. One patient had von Hippel-Lindau syndrome, 4 patients had diabetes mellitus, 3 patients had metastatic cancer, and 2 patients had ovarian tumors. CONCLUSIONS: Serous cystadenoma is an uncommon neoplasm that can be confused with malignancy both clinically and radiologically; a correct diagnosis is important in order to provide an accurate prognosis.

Metastases to soft tissue: a review of 118 cases over a 30-year period.

BACKGROUND: Metastatic tumors presenting as soft tissue masses are relatively rare and can be the source of diagnostic confusion both clinically and pathologically. The authors' experience was reviewed at a large academic medical center over a 30-year period (1971-2000) with metastases to soft tissue. METHODS: The tumors in the study included mainly lesions involving skeletal muscle or skeletal muscle and subcutaneous tissue of the upper and lower limbs, trunk, shoulders, and buttocks. Direct extension from tumors originating in bone or adjacent organs, tumors involving the skin or areas known to contain abundant lymph nodes (ie, axilla, groin), and hematopoietic malignancies were excluded. RESULTS: One hundred and eighteen cases were identified; 60 patients were women and 58 were men. The age range was 20 to 87 years (median of 53.5 years). The primary tumor was located in the skin (19 patients), lung (13 patients), breast (13 patients), kidney (12 patients), colon and rectum (12 patients), uterus (8 patients), ovary (5 patients), head and neck (tongue, pharynx, larynx, nasal cavity, and mandible) (5 patients), esophagus (2 patients), stomach (2 patients), cervix (2 patients), small bowel (2 patients), bone (2 patients), adrenal gland (1 patient), eye (1 patient), testis (1 patient), urinary bladder (1 patient), and salivary gland (1 patient). In 27% (32 of 118 cases) of cases, the soft tissue metastasis was the initial manifestation of the disease. In 13.5% (16 of 118 cases) of cases the primary site of origin could not be identified. The sites of metastasis included the abdominal wall (25 patients), back, including scapular region (20 patients), thigh (17 patients), chest wall (15 patients), arm (15 patients), shoulder (11 patients), buttock (5 patients), perineum (3 patients), leg (2 patients), foot (1 patient), umbilical area (1 patient), ankle (1 patient), scalp (1 patient), and elbow (1 patient). The histologic classification of the tumors included carcinoma (83 patients), malignant melanoma (20 patients), sarcoma and carcinosarcoma (9 patients), malignant mixed Mullerian tumor (2 patients), seminoma (1 patient), malignant teratoma (1 patient), malignant gastrointestinal stromal tumor (1 patient), and neuroblastoma (1 patient). Many of the tumors displayed histologic features that created difficulties for diagnosis and could be easily mistaken on routine histopathologic examination for a variety of primary soft-tissue sarcomas. Routine use of immunohistochemical stains aided in their proper recognition. CONCLUSIONS: Metastases are not an infrequent finding in soft tissue and they may represent the initial manifestation of the disease. Use of a basic panel of immunohistochemical stains is recommended for defining the cell type and arriving at the correct diagnosis.

Assessment of TCR-beta clonality in a diverse group of cutaneous T-Cell infiltrates.

While some unequivocally benign infiltrates are easy to distinguish from cutaneous T-cell lymphoma (CTCL), drug-associated lymphomatoid hypersensitivity reaction and cutaneous lesions of collagen vascular disease can show cytologic atypia, clonality and an immunophenotypic profile that closely simulates CTCL and cause diagnostics difficulties. Similar immunophenotypic and molecular abnormalities to those of malignant lymphoma can also be observed in pityriasis lichenoides chronica (PLC), large plaque parapsoriasis (LPP), pigmented purpuric dermatosis (PPD) and atypical lymphocytic lobular panniculitis leading one to consider these entities as forms of cutaneous lymphoid dyscrasia. The purpose of our study was to evaluate the distinction of these various subcategories of cutaneous T-cell infiltrates by assessment of T-cell receptor (TCR)-beta gene rearrangement. Formalin-fixed paraffin-embedded skin biopsies from 80 patients containing a T-cell dominant lymphocytic infiltrate were analyzed for TCR-beta gene rearrangement. Our findings indicate that monoclonality is a reliable characteristic of CTCL with polyclonality being very infrequent. However, some cases of drug associated lymphomatoid hypersensitivity, collagen vascular disease and the various cutaneous lymphoid dyscrasias (i.e. PLC, PPD and atypical lymphocytic lobular panniculitis) could manifest restricted molecular profiles in the context of an oligoclonal process or frank monoclonality.

Expression of immunohistochemical markers in primary and metastatic malignant melanoma: a comparative study in 70 patients using a tissue microarray technique.

Melanoma can show a broad spectrum of immunoreactivity and exhibit aberrant expression of antigens or changes in immunophenotype, particularly at metastatic sites. We studied 70 primary melanomas and their metastases with a broad panel of immunohistochemical markers using a tissue microarray technique to determine possible antigenic shift between the primary lesions and their metastases. Representative tissue cores were taken and processed from each case, and the tissue microarrays were stained by standard methods using antibodies to vimentin, bcl-2, CD117, carcinoembryonic antigen, epithelial membrane antigen, S-100 protein, HMB-45, cytokeratin AE1/AE3, Melan-A, TTF-1, CD99, and tyrosinase. Histologically, all the melanomas were of the classic epithelioid type. A slight increase in the expression of Melan-A was noted in metastatic lesions as opposed to the primary tumors (63% vs. 48.4%). Expression of other melanoma-associated markers, including S-100 protein and tyrosinase was only slightly decreased at metastatic sites as opposed to the primary tumor. Increased aberrant expression of epithelial-associated markers, including epithelial membrane antigen and cytokeratin AE1/AE3 was also noted in the metastases. bcl-2, CD117, and TTF-1 also showed a modest increase in antigenic expression at metastatic sites over the primary lesions. The results of this study demonstrated minimal antigenic shift between primary and metastatic melanoma for some of the more conventional melanocytic markers, it showed increased expression of aberrant markers and oncogene expression at metastatic sites.

The Toker tumor: spectrum of morphologic features in primary neuroendocrine carcinomas of the skin (Merkel cell carcinoma).

Primary neuroendocrine carcinoma of the skin is a relatively rare tumor that was first described by Cyril Toker in 1972. Since the seminal paper by Toker based on simple morphologic observations and detailed clinical correlation, our understanding of the clinical, morphological, and biological attributes of these lesions has grown exponentially with their increased awareness by pathologists and clinicians as well as with the many contributions of modern diagnostic techniques. The present review focuses principally on the various morphologic appearance that these tumors are able to adopt, the role of modern special techniques for diagnosis, and the conditions that need to be considered in their differential diagnosis.

Differential expression of smooth muscle myosin, smooth muscle actin, h-caldesmon, and calponin in the diagnosis of myofibroblastic and smooth muscle lesions of skin and soft tissue.

The diagnosis of low-grade and pseudosarcomatous spindle cell lesions of skin and soft tissue can sometimes be problematic; in particular, distinction between fibroblastic, myofibroblastic, and smooth muscle proliferations can occasionally pose difficulties on routine histologic examination. We have applied a panel of immunohistochemical markers to a series of spindle cell lesions of skin and soft tissue to assess the utility of the differential expression of smooth muscle and myofibroblastic-associated markers. Twenty-eight cases of nodular fasciitis, 42 cases of fibromatosis, and 3 cases of myofibroblastic sarcoma were stained with antibodies against smooth muscle actin (SMA), smooth muscle myosin (SMMS), calponin, and high-molecular weight caldesmon (h-caldesmon). For comparison, 12 cases of cutaneous leiomyoma and 8 cases of leiomyosarcomas involving superficial soft tissues and fascia were studied with the same panel of antibodies. Thirty-eight of 42 cases of fibromatosis were positive for SMA, 42/42 cases were positive for calponin, 39/42 cases were negative for SMMS, and all cases were negative for h-caldesmon. All cases of nodular fasciitis were positive for SMA and calponin, and all were negative for h-caldesmon and SMMS. All cases of myofibroblastic sarcoma were positive for SMA and 2/3 cases for calponin, and were negative for SMMS and h-caldesmon. All cases of cutaneous leiomyoma and leiomyosarcoma were positive for all 4 markers tested. Our results demonstrate a remarkably consistent pattern of reactivity of muscle and myofibroblastic-associated markers in lesions predominantly composed of myofibroblastic spindle cells, characterized by positive staining for SMA and calponin and absence of reactivity for SMMS and h-caldesmon. Application of this panel of stains may be of aid in the differential diagnosis of low-grade myofibroblastic lesions such as nodular fasciitis and fibromatosis from smooth muscle tumors of skin and soft tissue. This panel may additionally be of assistance in the diagnosis of myofibroblastic sarcoma.

Lipoblastic nerve sheath tumors: report of a distinctive variant of neural soft tissue neoplasm with adipocytic differentiation.

Benign nerve sheath tumors of soft tissue can occasionally adopt unusual or unfamiliar morphologic appearances that may introduce difficulties for diagnosis, such as multinucleation, bizarre nuclei, intranuclear vacuoles, and other degenerative changes. Tumor cells adopting a signet-ring or lipoblast-like configuration, however, are mostly associated with epithelial malignancies, liposarcoma and melanoma, and have been only rarely observed in spindle cell tumors of soft tissue. We report 5 cases of benign nerve sheath neoplasms that displayed prominent signet-ring cells with lipoblast-like features. The cases presented as solitary soft tissue masses in the groin, thigh, retroperitoneum, and shoulder in 4 men and 1 woman between the ages of 31 to 57 years. Four tumors predominantly showed features of schwannoma and one of neurofibroma; however, intimately admixed with the spindle cell population, there were also numerous scattered mature adipocytes as well as lipoblast-like cells displaying a signet-ring cell appearance. Immunohistochemical studies showed strong S-100 protein positivity in the spindle cells as well as in the signet-ring lipoblast-like cells and the mature adipocytes. The signet-ring cells were negative for mucin stains, cytokeratin, EMA, CEA, and several other differentiation markers. Ultrastructural examination was performed in 2 cases. The signet-ring cells contained large cytoplasmic lipid droplets that displaced the nuclei to the periphery, consistent with lipoblastic differentiation, whereas complex, interdigitating cytoplasmic processes covered by basal lamina material characteristic of nerve sheath differentiation could be identified in the spindle cells. Four patients for whom follow-up was available were alive and well with no evidence of recurrence over a period of 28 to 116 months (median follow-up, 50 months). The presence of mature fat and signet-ring lipoblast-like cells within a nerve sheath neoplasm is quite rare and may signify a process of aberrant differentiation. Neurogenic tumors should be added in the differential diagnosis of spindle cell tumors capable of displaying prominent signet-ring cell features.

Sclerosing paraganglioma: report of 19 cases of an unusual variant of neuroendocrine tumor that may be mistaken for an aggressive malignant neoplasm.

Nineteen cases of a distinctive variant of paraganglioma characterized by extensive collagen deposition resulting in a pattern of growth that resembled an invasive malignant neoplasm are described. The patients were 3 men and 16 women, 32 to 69 years of age (mean, 50.5 years). The tumors were located in the carotid body region, parapharyngeal region, and mediastinum. Tumor size ranged from 2 to 6 cm in greatest diameter. Grossly, the tumors were described as rubbery to firm, tan-red, and with extensive areas of sclerosis. Histologic examination showed nests and cords of tumor cells separated by broad bands of fibrous tissue. The tumor cells ranged from round to polygonal with abundant cytoplasm to elongated spindle cells with scant cytoplasm. Nuclear cytomegaly was present focally enhancing the atypical appearance of the tumor cell population in 17 cases. Mitoses were sparse (<1 x 10 HPF), and there was no evidence of necrosis in any of the cases. Foci of vascular and perineural invasion were present in 2 and 4 cases, respectively. The most striking morphologic feature was the presence of irregular cords and bands of hyalinized fibrous tissue that compartmentalized the lesion into irregular nests, islands, or cords of tumor cells, imparting them with an infiltrative appearance. All the tumors showed positive immunostaining for chromogranin, synaptophysin, and monoclonal neuron specific enolase. S-100 protein stains identified a sustentacular cell network, whereas cytokeratin AE1/AE3 was negative in all cases. Clinical follow-up in 14 cases, ranging from 2 months to 20 years (mean follow-up, 6.6 years) showed evidence of local recurrence in 2 cases and the development of a separate tumor in the contralateral neck in 1 case. The remainder of patients were free of recurrence or metastasis following simple local excision. Because of the prominent sclerosis, a diagnosis of an invasive malignant neoplasm was initially considered in the majority of cases. Sclerosing paraganglioma should be included in the differential diagnosis of sclerosing lesions of the head and neck region and mediastinum. Appropriate immunohistochemical stains may be of aid for establishing the correct diagnosis.