Invasive squamous cell carcinoma within a plaque of circumscribed palmar hypokeratosis.

Circumscribed palmar hypokeratosis (CPH) is a localized disorder of epidermal keratinization that is presented as a well-delimited, depressed, erythematous plaque on the palms or on the soles. It is histopathologically characterized by an abrupt thinning of the corneal epidermal layer. CPH is considered a benign condition, but a few cases with dysplastic changes/carcinoma in situ in the hypokeratotic epidermis have been described. We report hereby a case of invasive squamous cell carcinoma developed within a plaque of CPH. The pathogenesis of the malignant changes in this disorder remains to be clarified. Clinicians should be aware of the potential for developing malignancy in CPH and carry out a closer follow-up of this disorder.

Cutaneous leishmaniasis: A pathological study of 360 cases with special emphasis on the contribution of immunohistochemistry and polymerase chain reaction to diagnosis.

BACKGROUND: Traditional methods for the diagnosis of leishmaniasis yield poor sensitivity, which limits its effectiveness in lesions with a low parasite burden. METHODS: Retrospective pathologic study of 360 cases of cutaneous leishmaniasis and analysis of the different diagnostic methods used. RESULTS: In 93% of the lesions, histopathology showed a dense and diffuse inflammatory infiltrate, consisting of lymphocytes, histiocytes and plasma cells, which occupied the superficial and mid dermis and variably extended to deep dermis and superficial subcutis (standard pattern). The remaining cases exhibited atypical features, such as perivascular, interstitial or perifollicular inflammatory patterns, folliculitis or panniculitis. Granulomas were identified in 84% of biopsies, most of them as small, poorly formed, non-necrotizing histiocytic aggregates. Amastigotes were visualized by routine histopathologic exam in 36% of biopsies. Immunohistochemistry stained 17 of 26 lesions (65%) negative by conventional stains. PCR provided the correct diagnosis in 218 cases (58% of the series) negative for Leishmania by other techniques. CONCLUSIONS: Biopsies negative for Leishmania by traditional diagnostic methods that show the histopathologic standard pattern, those with atypical features from patients with clinical suspicion of cutaneous leishmaniasis in endemic areas, should be studied by immunohistochemistry and/or PCR for Leishmania in order to reach the definitive diagnosis.

High-risk Human Papillomavirus Determination in Formalin-fixed, Paraffin-embedded Cervical Tissue Using the Roche Cobas 4800 System: A Comparative Study With Liquid-based Cytology.

Roche cobas 4800 human papillomavirus (HPV) test is an automated real-time polymerase chain reaction-based system that allows the simultaneous detection of 14 human papillomavirus high-risk (HR-HPV) genotypes. This test is Food and Drug Administration approved since 2011 for HPV determination in liquid-based cytologic samples, but a clinically validated technique for formalin-fixed, paraffin-embedded (FFPE) tissue specimens is presently not commercially available. In our laboratory, we have developed an HPV detection procedure in FFPE tissue by cobas 4800 HPV test. In order to validate our method, we retrospectively studied 165 FFPE cervical biopsy and conization specimens with varied diagnoses from our files. In 50 of them, we contrasted the results with those obtained from simultaneous liquid-based cytologies from the same patients. Finally, seeking the possible complementary clinical usefulness of the procedure, we compared the HPV genotypes detected in cervical intraepithelial neoplasia grade 1 (CIN1)-diagnosed biopsies from 20 patients with a subsequent high-grade CIN (CIN2+) diagnosis with those from another group of 20 patients without a subsequent CIN2+ diagnosis. Eighty-seven percent of the assays provided informative results. HR-HPV was detected in 28 of 32 (88%) invasive cervical squamous carcinomas. Coincidental HR-HPV genotypes were obtained in 32 of 50 (64%) cases with simultaneous cervical biopsy and liquid-based cytologic samples. A significant higher risk of progression to CIN2+ was found when HPV16 (P=0.022) or any HR-HPV genotype (P=0.037) was detected in CIN1 biopsies. The reported procedure provides an automated, technically time-saving, easy to integrate into laboratory routine, and reliable method of HR-HPV determination in FFPE specimens.

Solitary Fibrous Tumor of the Vulva: Report of 2 Cases, Including a De Novo Dedifferentiated Solitary Fibrous Tumor Diagnosed After Molecular Demonstration of NAB2-STAT6 Gene Fusion.

Solitary fibrous tumor (SFT) is a neoplasm of fibroblastic lineage that has been documented in almost every anatomic location. Vulval SFT is very rare with only 10 cases reported to date. We present 2 additional SFTs located in the vulva, in adult women of 59 and 25 yr of age. The first showed a classic morphology and immunophenotype with uniform and strong STAT6 nuclear expression. The other one was a spindle-cell de novo dedifferentiated SFT with heterogeneous nuclear and cytoplasmic STAT6 staining, which could only be correctly diagnosed after molecular analysis with demonstration of a NAB2-STAT6 gene fusion. This genetic aberration is considered to represent the major pathogenic driver in SFT and is highly specific for this neoplasm. The differential diagnosis of vulval SFT is wide and varies depending on the histologic SFT subtype. Molecular analysis is mandatory for a correct diagnosis in cases without the characteristic histopathologic and immunophenotypical features.

Pleomorphic dermal sarcoma: a more aggressive neoplasm than previously estimated.

BACKGROUND: Pleomorphic dermal sarcoma (PDS) is a rare neoplasm sharing pathological features with atypical fibroxanthoma, but adding tumor necrosis, invasion beyond superficial subcutis or vascular or perineural infiltration. Although its metastatic risk has been estimated to be less than 5%, its real outcome is presently uncertain because of its rarity and to the lack of homogeneous criteria used in reported cases. METHODS: Retrospective clinicopathological study of 18 cases of PDS. RESULTS: The lesions presented as tumors or plaques (size: 7-70 mm) on the head of elderly patients (median: 81 years), without a gender predominance. Histopathologically, they consisted of spindle cells arranged in a fascicular pattern, containing pleomorphic epithelioid and giant multinucleated cells in varying proportions, and usually exhibiting numerous mitotic figures and infiltrative tumor margins. No immunoexpression for cytokeratins, S100 protein, desmin or CD34 was observed. Necrosis and venous invasion were found in three tumors each (17%). Follow-up was available in 15 cases (median: 33 months). Three patients (20%) had local recurrences, all with incomplete primary surgical resections. Three patients (20%) developed distant metastases in the skin, regional lymph nodes and/or lungs and died from the disease. CONCLUSION: Our data suggest that PDS may be a more aggressive neoplasm than previously estimated.

Clear Cell Atypical Fibroxanthoma: Clinicopathological Study of 6 Cases and Review of the Literature With Special Emphasis on the Differential Diagnosis.

Atypical fibroxanthoma (AFX) is an uncommon dermal-based neoplasm arising on the sun-damaged skin of elderly people. Clear cell AFX is a rare variant with only 12 cases reported until the present date, all of them as case reports, except for 1 small series of 3 cases. The authors report 6 new cases and review the literature with special emphasis on the differential diagnosis. The clear cell variant represents 5% of AFX from their files. Histopathologically, it consists of sheets of epithelioid, pleomorphic cells, intermixed with a varying number of giant multinucleated and spindle cells, the latter arranged in a fascicular pattern. All cell types predominantly exhibit a clear, microvacuolated cytoplasm with well-demarcated cell borders. The clinical and immunohistochemical features of this variant are similar to those of the classic type. Clear cell AFX must be differentiated from other cutaneous clear cell neoplasms, some of them with an aggressive clinical behavior, including clear cell melanoma, primary cutaneous and metastatic clear cell carcinomas, clear cell sarcoma, pleomorphic liposarcoma, tumor of perivascular epithelioid cells, and distinctive dermal clear cell mesenchymal neoplasm. The clinical presentation and immunohistochemical profile play a key role in the differential diagnosis.

Defining Ewing and Ewing-like small round cell tumors (SRCT): The need for molecular techniques in their categorization and differential diagnosis. A study of 200 cases.

BACKGROUND: Differentiation of Ewing sarcoma family of tumors (ESFT) and Ewing-like tumors remains problematic. Certain ESFT with morphological and immunohistochemical (IHC) profiles lack the EWSR1-ETS transcript. To improve diagnostic accuracy we investigated the presence of several specific transcripts in 200 small round cell tumors (SRCT) displaying ESFT morphology and immunophenotype in which EWSR1 FISH analysis was non-informative or negative. DESIGN: 200 tumors (formalin-fixed, paraffin-embedded) were analyzed by RT-PCR. All tumors were tested for EWSR1-ETS, EWSR1/WT1, PAX3/7-FOX01 or SYT/SSX transcripts, and the negative tumors were subsequently analyzed for CIC/DUX4, BCOR/CCNB3 and CIC/FOX04 transcripts. RESULTS: 133 (66.5%) ESFT displayed one of the above EWSR1-ETS translocations. Three cases (1.5%) revealed the SYT-SSX transcript for Synovial sarcoma, and one (0.5%) a EWSR1-WT1 transcript for Desmoplastic Small Round Cell tumor. The CIC-DUX4 translocation was found in six Ewing-like tumors (3%) with CD99 positivity. The BCOR-CCNB3 gene fusion was observed in 5 tumors (2.5%) displaying round or spindle cells with strong CCNB3 IHC expression in 3 tumors. Moreover, RT-PCR failed to detect any gene fusion transcripts in 19 tumors (9.5%) and were considered "undifferentiated small round cell sarcoma" (SRCS). Molecular biology results were non-informative in 33 SRCTs (16.5%) due to RNA degradation through inadequate fixation and/or decalcification. CONCLUSION: Our analysis of 200 SRCTs confirms the molecular heterogeneity of neoplasms with ESFT morphology and highlight that molecular studies with RT-PCR including new emerging gene fusion transcripts are mandatory for the diagnosis when EWSR1 FISH is negative or non-informative. The incidence of CIC-DUX4, BCOR-CCNB3 and CIC-FOX04 transcripts was relatively low. A small group of Ewing-like sarcomas or undifferentiated SRCS remains unclassified. Adopting appropriate tissue fixation and processing protocols is important to avoid degradation of fixed/embedded tissue when no frozen tumor is available.

[Atypical leiomyoma in a patient with cutaneous leiomyomatosis and mutation of the enzyme fumarate hydratase]. / Leiomioma cutáneo atípico en un paciente con leiomiomatosis cutánea y mutación de la enzima fumarato hidratasa.

We report the case of a 56 year-old male with an atypical leiomyoma in the context of a cutaneous leiomyomatosis and a family history of uterine leiomyomatosis. The genetic study revealed a mutation in the gene for the enzyme fumarate hydratase, but he has not had any renal malignancy so far. Atypical leiomyoma is a rare tumor that usually presents as a single lesion and is exceptional in patients with cutaneous leiomyomatosis. The relation between fumarate hydratase enzyme mutations with multiple leiomyomas, uterine leiomyomatosis and an increased risk of developing kidney cancer is widely known. However, the role of these mutations in the development of atypical leiomyomas is still impossible to clarify given the few cases reported in the literature.

Syringocystadenocarcinoma papilliferum in situ: report of a case with late recurrence.

Syringocystadenocarcinoma papilliferum (SCACP) is an extremely rare cutaneous neoplasm with apocrine differentiation. Only 27 cases have been reported up-to-date, 8 of them described as carcinomas in situ. Two cases with local recurrence and 3 cases with regional lymph node metastases have been documented. The authors present the case of a 32-year-old female with a SCACP in situ on the scalp that recurred 8 years after the excision of the primary tumor. No SCACP with late recurrence have been previously reported. This case highlights the need for a long-term follow-up in patients with this type of carcinoma.

Unilateral and pruritic papules: segmental Darier-White disease.

Darier-White disease is an uncommon disorder, which presents in a localized pattern in about 10% of patients, usually without nail, mucosa, or acral involvement. Type-1 is the most common of the segmental Darier-White disease types: papules have unilateral distribution along Blaschko lines. A 36-year-old woman diagnosed with type-1 segmental Darier-White disease is reported herein.

Self-regressing S100-negative CD1a-positive cutaneous histiocytosis.

In the skin, the antigen-presenting cells are mainly represented by Langerhans cells, indeterminate cells, and interstitial dendritic cells, which show distinctive immunophenotype and/or ultrastructure. We report a case of a cutaneous-limited self-regressing histiocytosis with a peculiar immunohistochemical profile (CD1a-positive and S100 protein-negative) that is not observed in any of the known cutaneous antigen-presenting cell or nowadays recognized neoplasm. This lesion is probably related to indeterminate dendritic cell tumors, but very few cases with such immunoprofile have been reported up-to-date, and their exact nosologic position and outcome remain to be clarified.

Cutaneous leishmaniasis with histopathologic pattern of non-necrotizing granulomatous dermatitis in patients treated with adalimumab.

Human leishmaniasis produced by Leishmania infantum is endemic in Mediterranean countries. In the context of a leishmaniasis outbreak in the town of Fuenlabrada, Madrid, Spain, we had two patients with cutaneous leishmaniasis that developed non-necrotizing cutaneous granulomas. They had both been receiving anti-TNF treatment with adalimumab for rheumatic diseases. Neither of them developed visceral disease and did not require anti-TNF treatment withdrawal to control the cutaneous disease. It is well known that anti-TNF therapy is associated with opportunistic diseases, especially with those in which granuloma formation is an important part of the host defence, as in tuberculosis. We think that granuloma formation through activation of Toll-like receptor-9 and via induction of a Th17 response may be precipitated by the parasites in the dermis.

Dermatomyofibromas presenting in pediatric patients: clinicopathologic characteristics and differential diagnosis.

Dermatomyofibroma represents a rare benign fibroblastic/ myofibroblastic cutaneous tumor that mostly occurs in young adult women. It has been seldom reported in pediatric patients. In this analysis, the clinical, histopathological and immunohistochemical findings of 12 dermatomyofibromas occurring in patients up to 16 years of age are compared with those reported in adults. Six patients were male and six were female. Nine lesions were located on the neck, two on the back and one involved the chest. The usual presentation was as an asymptomatic plaque composed of bland spindled cells arranged in dermal fascicles that were oriented parallel to the epidermis. Immunohistochemically, the lesional cells expressed calponin in 11 cases, smooth muscle actin in six and muscle-specific actin in three. In contrast to prior reports from adults, dermatomyofibromas in pediatric patients do not show a female predilection. In addition, they are mostly located on the neck (56%), while in adults the most frequent location is the shoulder (35%). Dermatomyofibromas seem to stabilize after an initial period of enlargement. Punch biopsy and clinical follow up could be an alternative approach to the surgical excision in some cases of dermatomyofibroma, particularly in instances in which surgery might inflict cosmetic defects.

Leiomyomatous nodules in a cellular angiofibroma: a hitherto unreported finding.

Cellular angiofibroma is a benign tumor of the superficial soft tissues of the vulvovaginal and inguinoscrotal regions of adult patients. Histologically, it is characterized by bland spindle cells arranged without any pattern in a stroma with thin collagen fibrils and evenly distributed small- to medium-sized blood vessels with hyalinized walls. The case of a 44-year-old female with a perineal cellular angiofibroma containing small leiomyomatous nodules is described in this case report. These nodules could probably be originated from smooth muscle differentiation of the spindle cell component of an otherwise conventional cellular angiofibroma. To our knowledge, the finding of distinct leiomyomatous nodules within a cellular angiofibroma has not been previously reported.

CD34-reactive tumors of the skin. An updated review of an ever-growing list of lesions.

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.

CD34-reactive tumors of the skin. An updated review of an ever-growing list of lesions.

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma (ES) or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.

Superficial acral fibromyxoma: report of 4 cases with CD10 expression and lipomatous component, two previously underrecognized features.

Superficial acral fibromyxoma (SAF) is an uncommon tumor of the superficial soft tissues of acral extremities in middle-aged adults, firstly described in a series of 37 cases by Fetsch et al. in 2001. Since then, just a few case reports have been published. It is histologically characterized by a slightly to moderately cellular proliferation of spindled and stellate-shaped bland fibroblastic cells, arranged in a random, loose storiform, or fascicular growth pattern, within a myxoid, myxocollagenous, or collagenous stroma, with a prominent vasculature. The cells express CD34, CD99, and, frequently, epithelial membrane antigen. We report 4 cases that show clinical, morphological, and immunohistochemical characteristics of SAF and, additionally, exhibit two features rarely documented in previous publications, such as CD10 expression and a lipomatous component. Three of our 4 cases express CD10. The single previously reported case tested for CD10 was also positive. One of our cases contains mature fat cells intermingled with the spindle cells throughout the lesion. This finding has not been documented before in SAF. Our small series shows that SAF frequently expresses CD10 and occasionally can have a lipomatous component.