HPV Status Improves Classification of Head and Neck Gray Zone Cancers.

In epidemiologic studies, patients with head and neck squamous cell carcinoma (HNSCC) are classified mainly by the International Classification of Diseases (ICD) codes. However, some patients are of an unclear subsite, the "gray zone" cases, which could reflect ICD coding error, absence of primary subsite, or extensive primary tumors that cross over multiple subsites of the oral cavity and oropharynx. Patients with gray zone squamous cell carcinomas were compared with patients with oral cavity squamous cell carcinoma (OSCC) or oropharyngeal squamous cell carcinoma (OPSCC) and stratified by human papillomavirus (HPV) status that was determined by p16 immunostaining or HPV serology. Comparisons consisted of clinicodemographic features and prognostic outcomes presented by Kaplan-Meier curves and Cox proportional hazards regression models, reported as hazard ratios. There were 158 consecutive patients with gray zone HNSCC diagnosed at the Princess Margaret Cancer Center between 2006 and 2017: 66 had subsite coding discrepancies against the clinician's documentation ("discrepant" cases; e.g., the diagnosis by the clinician was OSCC, while the classification by ICD coding was OPSCC), while 92 were squamous cell carcinoma of unknown primary of the head and neck (SCCUPHN) after complete diagnostic workup. Comparators included 721 consecutive OSCC and 938 OPSCC adult cases. All HPV-positive cohorts (OPSCC, discrepant, and SCCUPHN) had similar clinicodemographic characteristics and better 3- and 5-y overall survival and disease-free survival than their HPV-negative counterparts. In contrast, HPV-negative discrepant cases had prognostic outcomes most similar to HPV-negative OPSCC cases, while HPV-negative SCCUPHN had survival outcomes most similar to those of patients with OSCC in this study. HPV-positive status can improve the classification of patients with unclear or discrepant oral/oropharyngeal subsite, an improvement over classification systems that are solely clinician defined or conducted through ICD coding. However, due to clinical practice, we could not make definitive reclassification for patients with HPV-negative gray zone HNSCC.

Radiologic-Pathologic Correlation of Tumor Thickness and Its Prognostic Importance in Squamous Cell Carcinoma of the Oral Cavity: Implications for the Eighth Edition Tumor, Node, Metastasis Classification.

BACKGROUND AND PURPOSE: Addressing the performance of an imaging-based parameter compared to a "gold standard" pathologic measurement is essential to achieve accurate clinical T-classification. Our aim was to determine the radiologic-pathologic tumor thickness correlation and its prognostic value in oral squamous cell carcinoma. MATERIALS AND METHODS: All pathologic T1-T3 (seventh edition of the Cancer Staging Manual of the American Joint Committee on Cancer) oral squamous cell carcinomas diagnosed between 2010 and 2015 were reviewed. Radiologic tumor thickness was measured on preoperative CT or MR imaging blinded to pathology. The radiologic-pathologic tumor thickness correlation was calculated. The impact of the imaging-to-surgery time interval and imaging technique on the correlation was explored. Intra-/interrater reliability on radiologic tumor thickness was calculated. The correlation of radiologic-versus-pathologic tumor thickness and its performance as the seventh edition T-category modifier was evaluated. Multivariable analysis assessed the prognostic value of the radiologic tumor thickness for overall survival adjusted for age, seventh edition T-category, and performance status. RESULTS: For 354 consecutive patients, the radiologic-pathologic tumor thickness correlation was similar for the image-to-surgery interval of ≤4.0 weeks (ρ = 0.76) versus 4-8 weeks (ρ = 0.80) but lower in those with more than an 8-week interval (ρ = 0.62). CT and MR imaging had similar correlations (0.76 and 0.80). Intrarater and interrater reliability was excellent (0.88 and 0.84). Excluding 19 cases with an imaging-to-surgery interval of >8 weeks, 335 patients were eligible for further analysis. The radiologic-pathologic tumor thickness correlation was 0.78. The accuracy for upstaging the T-classification based on radiologic tumor thickness was 83% for pathologic T1 and 74% for pathologic T2 tumors. Multivariable analysis confirmed the prognostic value of radiologic tumor thickness (hazard ratio = 1.5, P = .02) for overall survival. CONCLUSIONS: This study demonstrates a good radiologic-pathologic tumor thickness correlation. Intrarater and interrater reliability for radiologic tumor thickness was excellent. Radiologically thicker tumor was predictive of inferior survival.

Molecular biology of squamous cell carcinoma of the head and neck.

Squamous cell carcinoma of the head and neck (HNSCC) is a heterogeneous but largely preventable disease with complex molecular abnormalities. It arises from a premalignant progenitor followed by outgrowth of clonal populations associated with cumulative genetic alterations and phenotypic progression to invasive malignancy. These genetic alterations result in inactivation of multiple tumour suppressor genes and activation of proto-oncogenes, including p16(ink4A), p53, cyclin D1, p14(ARF), FHIT, RASSF1A, epidermal growth factor receptor (EGFR), and Rb. Intramucosal migration and clonal expansion of transformed cells with formation of abnormal genetic fields appear to be responsible for local recurrences and development of second primary tumours.

Clinicopathological characteristics and cell cycle proteins as potential prognostic factors in myoepithelial carcinoma of salivary glands.

Myoepithelial carcinoma (MCA) is a rare malignancy of salivary glands that was included in the WHO Classification of Head and Neck Tumors in 1991. MCA has shown a broad spectrum of clinical outcomes, but attempts to identify prognostic markers for this malignancy have not resulted in significant progress. Conventional histopathological characteristics such as tumour grade, nuclear atypia, mitotic index and cell proliferation have failed to predict the outcome of MCA. In this study, we reviewed the histopathology of 19 cases of MCA focusing on nuclear atypia, mitotic count, tumour necrosis, nerve and vascular invasion and occurrence of a pre-existing pleomorphic adenoma in connection to the MCA. Histopathological characteristics and clinical information were correlated with the immunohistochemical expression of cell cycle proteins including c-Myc, p21, Cdk4 and Cyclin D3. The proportion of tumour cells immunoreactive for these markers and their intensity of staining were correlated with clinical information using logistic regression, Kaplan-Meier and Cox regression. Using logistic regression analysis, cytoplasmic c-Myc expression was associated with the occurrence of metastases (P = 0.019), but limitations of semi-quantitation of immunostaining and the limited number of cases preclude definitive conclusions. Our data show that the occurrence of tumour necrosis predicts poor disease-free survival in MCA (P = 0.035).

Follicular dendritic cell tumor: report of 13 additional cases of a distinctive entity.

Follicular dendritic cell (FDC) tumor is an extremely rare malignant neoplasm with approximately 17 well-documented cases in the literature. We report 13 additional cases of this distinctive neoplasm. There were seven men and six women, with a mean age of 46.5 years (range, 27-62 years). There was involvement of cervical lymph nodes (six cases), mediastinum (three cases), axilla, tonsil, spleen, and peripancreatic soft tissues (one case each). The neoplasms were grey to tan, ranging in size from 1 to 13 cm. They were formed by oval to spindle cells with eosinophilic cytoplasm growing in sheets and fascicles, with a focal storiform pattern and whorls reminiscent of those seen in meningioma. The nuclei were oval or elongated with thin nuclear membranes, inconspicuous or small eosinophilic nucleoli, and clear or dispersed chromatin. Typically, the tumor cells were intimately admixed with small lymphocytes, with a prominent perivascular cuffing. Multinucleated tumor cells were present in seven cases. Necrosis, marked cellular atypia, high mitotic rate, and/or abnormal mitoses were present in seven cases. The tumor cells were positive for CD21 (10 of 11), CD35 (10 of 11), Ki-M4p (seven of eight) Ki-FDRC1p (six of seven), vimentin (five of nine), and S100 protein (five of nine). One case stained with actin. In situ hybridization, done in six cases, did not show Epstein-Barr virus RNA sequences. Ultrastructural examination of eight cases showed long, complex, occasionally interdigitating cytoplasmic processes joined by desmosomes. The behavior of these tumors is more akin to that of a low-grade soft tissue sarcoma than a malignant lymphoma and is characterized by local recurrences and occasional metastases. Two patients died of tumor, two were alive with recurrent or metastatic disease, eight were alive with no disease, and one was lost to follow-up.

Solid serous adenoma of the pancreas. The solid variant of serous cystadenoma?

Serous cystadenomas of the pancreas are uncommon benign neoplasms that occur most frequently in elderly females. Characteristically, the tumors have a spongy gross appearance and are composed of innumerable cysts lined by flat, cuboidal, and polygonal cells with clear to pale eosinophilic cytoplasm and round, hyperchromatic central nuclei. Macrocystic variants with an oligolocular gross appearance have also been described. In this report we describe a solid pancreatic neoplasm arising in a 70-year-old woman who remains well 5 years after a distal pancreatectomy. The well-circumscribed tumor measured 4.0 cm in maximal diameter and was formed by clear to pale polygonal to cuboidal cells arranged in nests, sheets, and trabeculae separated by thick fibrous bands. Although small acini with glandular spaces were present within the nests, cystic spaces were absent. Periodic acid-Schiff (PAS) and PAS-dismutase (PAS-D) stains revealed a large amount of cytoplasmic glycogen. The tumor cells were immunoreactive for CAM 5.2, epithelial membrane antigen, and neuron-specific enolase. The cytologic, histochemical, and immunohistochemical features of the tumor were indistinguishable from those of serous cystadenomas; therefore, we believe this solid serous adenoma represents a solid variant of serous cystadenoma. Recognition of this lesion is important because the vast majority of solid tumors in the pancreas are malignant. The differential diagnosis includes the rare primary clear-cell "sugar" tumor of the pancreas, clear cell carcinoma, clear cell islet cell tumor, and metastatic renal cell carcinoma.

Olfactory neuroblastoma is not related to the Ewing family of tumors: absence of EWS/FLI1 gene fusion and MIC2 expression.

The relationship of olfactory neuroblastoma to the Ewing sarcoma family of tumors remains controversial due to its variable histopathology and to conflicting or inconsistent cytogenetic, immunophenotypic, and molecular data. To address this issue, we performed a morphologic, immunohistochemical, and molecular study of 20 olfactory neuroblastomas. Morphologically, the tumors consisted of nests of primitive small, round, blue cells, usually set in a background of neurofibrillary stroma. Immunohistochemical stains revealed strong reactivity for neuroendocrine markers (synaptophysin, chromogranin, neuron-specific enolase) and only focal staining for cytokeratins in two cases. Immunostaining with antibody O13 to the Ewing sarcoma-associated MIC2 antigen was uniformly negative (0 of 17). Amplifiable RNA was extracted from paraffin-embedded tissue blocks of 11 cases, and no evidence of the chimeric EWS/FLI transcript, characteristic of Ewing sarcoma, was found in any case. The EWS gene was not rearranged using Southern blot analysis in one additional case in which high molecular weight DNA was available. These results disagree with the proposed classification of olfactory neuroblastoma in the Ewing sarcoma family of tumors and suggest that therapy developed for the latter tumor group may not be biologically rational for olfactory neuroblastoma.

Renal oncocytoma: a clinicopathologic study of 70 cases.

We reviewed 954 primary nonurothelial epithelial renal neoplasms with primary resection at Memorial Sloan-Kettering Cancer Center between the years 1980 and 1995 and classified 70 cases (7%) as renal oncocytomas. The study population was composed of 39 men and 31 women, and the mean age was 65 years (range 25 to 86 years). Fifty-six patients (80%) were asymptomatic at presentation, six (4%) had flank pain, six (4%) presented with a mass, and two (3%) had hematuria. Sixty-one were treated with total or radical nephrectomy, nine with partial nephrectomy. The right kidney was involved in 35 cases (50%), the left kidney in 32 (46%). Three cases (4%) were bilateral. Sixty-one cases (87%) were unifocal, nine (13%) multifocal. All the tumors were well circumscribed but unencapsulated. Forty-five (64%) were described as brown or red, whereas the remainder were variously described as tan to yellow. Central fibrosis or scar was described in 23 cases (33%), and gross areas of hemorrhage or cystic changes in 14 (20%). The mean size was 5.2 cm and median 5.0 cm (range 1.5 cm to 14 cm). Histologically, the tumors were characterized by a mixture of architectural patterns: compact cellular nests and acini embedded in a hyalinized, hypocellular stroma were present in 62 cases (89%), a solid nested architecture in 47 cases (67%), and a variable tubular component in 50 cases (71%). Small papillae, pseudopapillae, and intratubular epithelial tufts were seen in 19 cases (27%). Cytologically, the neoplasms also showed a mixture of cell types, the most common being the classic oncocyte, which consisted of round or polygonal cells with moderate to abundant granular, eosinophilic cytoplasm, and small round nuclei with evenly dispersed granular chromatin. Small basophilic nucleoli were visible in many of these cells in all cases. Thirty-one cases (44%) had a variable number of oncocytic cells with pyknotic nuclei and 20 (30%) contained clusters of small cells with a high nuclear/cytoplasmic ratio and dense hyperchromatic nuclei (so-called oncoblasts). Foci of tubules with clear cells embedded in a hyalinized stroma were present in six cases (9%). Cellular atypia was evident in 42 cases (60%) and was marked in 21 (30%). Eleven cases (16%) exhibited mitotic activity, albeit low. No case had atypical mitoses or necrosis. Twenty-two cases (31%) had areas of calcification within the hyalinized stroma, 12 (17%) had calcospherites, and three (4%) had osseous and myeloid metaplasia. Vascular invasion was present in three cases (4%), and invasion of perinephric fat in 14 (20%). One patient presented with liver metastasis. Fourteen cases (20%) were pT1, 42 (60%) pT2, and 14 (20%) pT3. After a mean follow-up of 58 months (range 1 to 181), 62 patients (89%) were alive with no evidence of tumor, six (9%) had died of other causes, one was alive with stable metastatic disease in the liver 58 months after diagnosis, and one died with metastatic disease to bone and liver. We conclude that renal oncocytomas have a varied morphologic appearance and their pathologic diagnosis should be based on a constellation of architectural and cytologic features. The overwhelming majority of cases behave in a benign fashion, although in rare instances they can metastasize. The presence of atypical morphologic features do not alter the excellent prognosis associated with oncocytomas and do not predict an aggressive clinical course.

Small cell neuroendocrine carcinoma of the nasal cavity and paranasal sinuses.

Small cell neuroendocrine carcinomas (SNECs) of the sinonasal tract are extremely uncommon tumors. We reviewed the clinicopathologic features of six cases of this neoplasm. There was no sex preponderance with three females and three males and a mean age at presentation of 51 years (range, 38 to 68). Two patients had disease limited to the nasal cavity, and in four the tumor involved the nasal cavity and maxillary or ethmoid sinuses. Involvement of the orbit was present in two patients. Surgery was the primary treatment. After a mean follow-up of 37 months, one patient died of local disease and liver metastases, four were alive with recurrent or metastatic disease, and one died of unrelated causes. The tumors were composed of sheets, nests, and trabeculae with extensive areas of necrosis and hemorrhage. The individual cells were small to intermediate in size and had scanty cytoplasm. The nuclei were oval or round and hyperchromatic with absent or inconspicuous nucleoli. Nuclear molding and crush artefact were present in five cases. All tumors had a high mitotic rate with frequent abnormal mitotic figures. All cases stained for Cam 5.2, neuron-specific enolase, and chromogranin. Five cases were positive for AE1:AE3, and four for synaptophysin. No case stained for S-100 protein, or neurofilaments. O-13 stained one case. No case contained EBV-RNA. SNECs of the nasal cavity and paranasal sinuses are aggressive tumors with pathological features similar to those of anaplastic small cell carcinomas of the lung. They exhibit morphological and immunophenotypic features different from olfactory neuroblastoma and should be distinguished from this tumor.

Expression of mismatch repair proteins, beta catenin, and E cadherin in intestinal-type sinonasal adenocarcinoma.

BACKGROUND: Despite their histological resemblance to colorectal adenocarcinomas, there is little information about the molecular events involved in the pathogenesis of intestinal-type sinonasal adenocarcinomas (ITACs). AIMS: To evaluate the possible role of DNA mismatch repair (MMR) gene defects or disruptions of the E cadherin-beta catenin complex in ITAC by investigating the immunohistochemical expression of the MMR gene products, beta catenin, and E cadherin in a group of sporadic ITACs. METHODS: Ten sporadic cases of ITAC were stained with antibodies against MLH1, MSH2, MSH3, MSH6, beta catenin, and E cadherin. RESULTS: Nine cases showed strong nuclear expression of MLH1, whereas one case showed moderate staining. All 10 cases were strongly positive for MSH2 and MSH3. MSH6 was strong in nine cases, and moderate in one. Membranous beta catenin expression was strong in all 10 cases, and no case showed cytoplasmic or nuclear staining. E cadherin was strong in seven cases, and moderate in three cases. CONCLUSIONS: The preserved nuclear expression of MLH1, MSH2, MSH3, and MSH6 suggests that mutations or promoter methylation of MMR genes do not play a role in the pathogenesis of ITAC. The strong membranous staining for E cadherin and beta catenin and lack of abnormal cytoplasmic or nuclear expression is in keeping with the preservation of E cadherin-beta catenin complexes and beta catenin pathways.

Expression pattern of CK7, CK20, CDX-2, and villin in intestinal-type sinonasal adenocarcinoma.

BACKGROUND: Intestinal-type sinonasal adenocarcinoma (ITAC) is an uncommon neoplasm, which resembles adenocarcinoma of the gastrointestinal tract. ITAC occurs sporadically or in association with occupational exposure to hardwood dust and other agents. AIMS: To investigate the phenotype and possible pathogenetic mechanisms of primary sinonasal and nasopharyngeal adenocarcinomas by staining for cytokeratin 7 (CK7), CK20, CDX-2, and villin. METHODS: Twelve sporadic sinonasal and nasopharyngeal adenocarcinomas were stained with monoclonal antibodies to CK7, CK20, CDX-2, and villin. The ITACs were classified as papillary, colonic, solid, mixed, or mucinous types. RESULTS: The diagnosis of ITAC was confirmed in 10 cases: five were colonic type and five were papillary. One was a sinonasal papillary low grade adenocarcinoma, and one a papillary nasopharyngeal adenocarcinoma, and these tumours were CK7 positive, but CK20, CDX-2, and villin negative. All ITACs were positive for CK20, CDX-2, and villin, and six were CK7 positive. One ITAC had a focus of intestinal metaplasia away from the invasive carcinoma. CONCLUSIONS: Sinonasal ITACs have a distinctive phenotype, with all cases expressing CK20, CDX-2, and villin. Most ITACs also express CK7, although a proportion of tumours are CK7 negative. ITAC seems to be preceded by intestinal metaplasia of the respiratory mucosa, which is accompanied by a switch to an intestinal phenotype. Although ITACs are morphologically similar, differences in cytokeratin expression patterns suggest two distinct types. The expression pattern of CK7, CK20, CDX-2, and villin positive may be useful in separating these tumours from other non-ITAC adenocarcinomas of the sinonasal tract and nasopharynx.

Malignant evolution of Schnitzler's syndrome--chronic urticaria and IgM monoclonal gammopathy: report of a new case and review of the literature.

Schnitzler's syndrome, initially described in 1974 is an uncommon condition defined by chronic urticaria and monoclonal IgM gammopathy. Additional features include fever of unknown origin, elevated ESR, bone pain and frequently a benign clinical course. We conducted a literature search of Medline, EMBASE and Cancerlit and found 56 cases of Schnitzler's syndrome reported to date. The absence of lymphoproliferative disease in this condition is typical, but nine patients have progressed to develop lymphoplasmacytic neoplasias, particularly Waldenstrom's macroglobulinemia (WM). Malignant evolution of Schnitzler's syndrome is a rare complication, but emphasizes the importance of long term follow-up and the need for these patients to undergo periodic assessment of the bone marrow and lymph nodes. Treatment of this condition is difficult, with varying response to corticosteroids and largely unsuccessful results with standard chemotherapy used for WM. We describe a case of Schnitzler's syndrome in a 50-year old man with lymphocytic aggregates in the bone marrow after 9 years of chronic urticaria, fever, arthralgias and bone pain. We review the clinical features and treatment, with emphasis on the hematologic aspects of this unusual condition.

Primary spinal epidural mantle cell lymphoma: case report.

OBJECTIVE AND IMPORTANCE: Mantle cell lymphoma is a distinct clinicopathological type of non-Hodgkin's lymphoma that often presents at an advanced stage, with systemic spread. Spinal involvement is uncommon and generally occurs as part of advanced disease or generalized relapses. Primary spinal epidural lymphoma is a rare initial manifestation of non-Hodgkin's lymphoma, and mantle cell lymphoma with initial presentation in the spinal epidural space is extremely rare, having been previously reported in only two cases. CLINICAL PRESENTATION: We report a case of a 71-year-old man who presented with increasing weakness and numbness of the legs. Magnetic resonance imaging revealed a spinal epidural mass in the lumbosacral region. INTERVENTION: The patient underwent a partial L4 and L5-S1 laminectomy, with incomplete resection of the mass for spinal decompression and tissue diagnosis. Mantle cell lymphoma was diagnosed in the pathological examination. CONCLUSION: After radiotherapy, the disease recurred with a soft-tissue mass in the anterior maxillary area of the face. The patient underwent restaging and was treated with chemotherapy, with only a partial response. Mantle cell lymphoma with primary spinal epidural presentation is rare. This diagnosis can be established and other causes of spinal cord compression can be ruled out by obtaining tissue for proper histopathological examinations. Because of its aggressive behavior and poor prognosis, mantle cell lymphoma should be treated using a combined-modality approach.

Epithelioid hemangioendothelioma of the spine presenting as cervical myelopathy: case report.

OBJECTIVE AND IMPORTANCE: We report the first case in the literature of cervical myelopathy caused by progressive cord compression as a result of epithelioid hemangioendothelioma of the cervical vertebra. CLINICAL PRESENTATION: A 58-year-old man presented with progressive cervical myelopathy. Imaging revealed a vascular, expansile lesion of contiguous cervical vertebrae causing cord compression. The surgical pathology revealed epithelioid hemangioendothelioma, a rare tumor not previously reported to present in such a fashion. INTERVENTION: Preoperative embolization and a two-stage anterior and posterior surgical decompression and fusion procedure were performed. The high vascularity of this lesion makes surgery a formidable surgical challenge. Adjuvant radiotherapy was administered to the residual tumor because of its potential for low-grade malignancy. CONCLUSION: The diagnosis relied on accurate histopathological assessment. The general principles of achieving cord decompression and tumor control are important. The literature on epithelioid hemangioendothelioma involving the spine is reviewed, and the tumor biology and the role of adjuvant therapy are discussed.

Malignant melanomas of the parotid: comparison of survival for patients with metastases from known vs unknown primary tumor sites.

BACKGROUND: Malignant melanoma (MM) rarely affects the parotid, and usually this diagnosis will herald a search for a primary skin neoplasm. Occasionally, no primary tumor is ever found, raising questions regarding prognosis and the issue of primary melanoma of the parotid. OBJECTIVE: To evaluate retrospectively the clinical and histological features of MM involving the parotid in 19 patients. DATA SOURCES: Pathology and hospital files at 3 tertiary care university hospitals. STUDY SELECTION: Patients with MM within the parotid with adequate histopathologic and immunohistochemical documentation, as well as clinical information regarding patient outcome. DATA EXTRACTION: In 6 patients, no extraparotid MM was ever identified. After parotidectomy, 5 patients (including 1 patient who died of other causes) were melanoma free at a mean of 4.2 years (range, 14 months to 7.5 years). Only 1 patient died of disease after 17 months. An extraparotid primary tumor was present in 13 patients, 10 with dermal and 3 with mucosal sites. At follow-up, only 1 of these patients was disease free after 2 years. Nine patients died of melanoma after a mean of 2.6 years (range, 10 months to 5 years); the other 3 had evidence of metastatic disease at a mean of 4.3 years (range, 3-6 years). Nondermal sites of primary tumors were the nasal cavity, sclera, and conjunctiva. DATA SYNTHESIS: Patients with metastatic MM from unknown primary tumors have a longer disease-free survival than those with metastases from known primary disease. CONCLUSIONS: Although rare, MM should be considered in the differential diagnosis of parotid tumors. Unusual mucosal or ocular sites should be considered in the search for possible primary tumor sites to avoid treatment delay. These data support the idea that patients with metastatic MM from unknown primary tumors may follow a more improved course than that of patients with metastases from known primary disease.

Rhabdomyosarcoma with rhabdoid-like features.

We describe an unusual case of a rhabdomyosarcoma (RMS) in that it had rhabdoid-like cells histologically and occurred in a female who had undergone bone marrow transplantation for chronic myelogenous leukemia. The tumor was composed of loosely cohesive cells with abundant eosinophilic cytoplasm and exhibited PAS-negative paranuclear inclusions. The tumor cells had positive vimentin, muscle-specific actin, sarcomeric actin and desmin immunoreactivity. Ultrastructurally, the tumor cells contained aggregates of thin and thick filaments. In situ hybridization did not detect human papillomavirus or cytomegalovirus DNA, or EBV DNA or RNA. The tumor fulfilled the current criteria for a diagnosis of RMS; however, it could not be further classified. The tumor appears to have a good prognosis as there has been no evidence of recurrence five years after resection. As this is the first case report, to our knowledge, of this type of tumor following bone marrow transplant, the significance of this association is not yet clear.

Mesothelial lesions of the paratesticular region.

Mesothelial lesions involving the paratesticular region include mesothelial cysts, reactive mesothelial hyperplasia, adenomatoid tumors, benign cystic mesothelioma, well-differentiated papillary mesothelioma, and malignant mesothelioma. The diagnosis and management of these lesions are often difficult for surgical pathologists, surgeons, and oncologists alike. Mesothelial lesions are relatively uncommon and most benign and malignant tumors present as testicular tumors with no specific findings. A preoperative diagnosis of malignancy is rarely made, and there is no established effective therapy for malignant mesothelioma. This article reviews the clinicopathologic features of paratesticular mesothelial lesions with emphasis in their differential diagnosis and prognosis.

Follicular dendritic cell tumor: review of the entity.

Malignant neoplasms showing follicular dendritic cell differentiation are uncommon. Most reported cases have involved lymph nodes of the neck, mediastinum, and axilla. Approximately 30% of the cases were located in extranodal sites, such as liver, tonsil, and intra-abdominal soft tissue. Microscopically, follicular dendritic cell tumor is composed of oval to spindle cells with eosinophilic cytoplasm arranged in sheets, fascicles, and whorls, sometimes admixed with foci showing a storiform pattern of growth. The tumor cells are characteristically admixed with small lymphocytes. The tumor nuclei are oval to spindle, with thin nuclear membranes, small basophilic nucleoli, and clear or dispersed chromatin. Scattered multinucleated tumor cells are frequently seen. Necrosis, marked cellular atypia, high mitotic rate, and abnormal mitoses may occur and are harbingers of an aggressive behavior. The tumor cells typically express CD21, CD35, Ki-M4p, Ki-FDRC1p, and vimentin, with occasional positivity for S-100 protein, muscle-specific actin, and epithelial membrane antigen. Ultrastructural examination shows complex interdigitating cytoplasmic processes joined by desmosomes. The behavior of these tumors is more akin to that of a low-grade soft tissue sarcoma than a malignant lymphoma and is characterized by local recurrences in 36% of cases and metastases in 28%. A small proportion of cases have arisen against a background of Castleman disease of the hyaline-vascular type and others in association with Epstein-Barr virus infection. Complete surgical resection is the treatment of choice whenever feasible. Adjuvant radiotherapy or chemotherapy appears indicated in cases having adverse pathological features and in recurrent or incompletely resected lesions. Much still needs to be learned about the most effective adjuvant therapy and the molecular biology of these tumors.

Metastatic adamantinoma diagnosed by fine-needle aspiration biopsy of the lung.

We report two cases of metastatic adamantinoma to the lung diagnosed by FNAB. The cytologic appearance of the smears of each case was homogenous, containing small round and spindle cells with indistinct cytoplasm. The nuclei had delicate nuclear membranes, with finely dispersed chromatin and occasional micronucleoli. No pleomorphism was noted. Immunocytochemistry exhibited positive staining for keratin and vimentin. EM examination revealed numerous tonofilaments and well formed desmosomes. The cytologic diagnosis of metastatic adamantinoma can be made with the knowledge of a previous history of adamantinoma of bone, the comparison of the metastatic tumor with the original bone tumor, and the awareness of the long latency of the metastases. Immunocytochemistry and EM are needed to substantiate the diagnosis.

Giant cell angiofibroma of the oral cavity: report of a new location for a rare tumor.

Giant cell angiofibroma is a rare, soft tissue tumor that was first described in the orbit. Since then, several case reports have described this tumor in a number of extra-orbital sites, suggesting a wider anatomic distribution than is generally recognized. The tumor typically acts in a benign fashion with only rare local recurrences but no tendency to metastatic disease. Here, we report the first case of a giant cell angiofibroma in the oral cavity. The tumor presented as a soft tissue nodule on the buccal mucosa of a 60-year-old man. The histologic differential diagnosis included a number of other uncommon soft tissue neoplasms, including giant cell fibroblastoma, solitary fibrous tumor, and pleomorphic lipoma. The histologic and immunohistochemical features of this tumor and differentiation from other histologically similar soft tissue neoplasms are briefly discussed.