Richard J. Zarbo

Renal angiomyolipoma: further immunophenotypic characterization of an expanding morphologic spectrum.

BACKGROUNDnRenal angiomyolipoma is a benign tumor histologically characterized by proliferation of spindle cells, epithelioid cells, and adipocytic cells in concert with many thick-walled blood vessels. To add further diagnostic confusion, an epithelioid cell-predominant variant of renal angiomyolipoma has recently been described. HMB-45 immunoreactivity correlates with ultrastructural striated organelles that closely resemble premelanosomes, although no evidence of melanogenesis has been documented in this tumor.nnnOBJECTIVEnTo further characterize the immunophenotypic and ultrastructural profile of renal angiomyolipoma based on phenotypic cell type (epithelioid, spindle, and adipocytic cell).nnnDESIGNnFormalin-fixed, paraffin-embedded tissues from 27 renal angiomyolipomas and 8 renal cell carcinomas were immunostained with monoclonal antibodies to the melanoma-associated antigens HMB-45, HMB-50, NKI/C3 (CD63), and tyrosinase; the smooth muscle-related antigens calponin and muscle-specific actin (HHF-35); S100; and cytokeratin (CK). All renal angiomyolipomas were also immunostained with a polyclonal antibody to renin. Ultrastructural examination was performed on 9 selected cases.nnnRESULTSnAll renal angiomyolipomas stained positive for HMB-45, HMB-50, NKI/C3, muscle-specific actin (HHF-35), and calponin. Overall, HMB-45, HMB-50, and NKI/C3 preferentially stained the epithelioid cells. Tyrosinase staining was present in 50% of the renal angiomyolipomas with adequate tissue for staining (12 of 24 cases); positive staining and intensity paralleled HMB-45, HMB-50, and NKI/C3. Muscle-specific actin (HHF-35) and calponin preferentially stained the spindle cells. The adipocytic cells stained positive for both melanoma-associated antigens and smooth muscle antigens. Epithelioid cells, spindle cells, and adipocytic cells were CK, S100, and renin negative. Ultrastructural findings paralleled immunohistochemical staining patterns. Premelanosome-like organelles and electron dense granules were more readily detected in the epithelioid cells within the tumor, whereas ultrastructural characteristics of smooth muscle cells were more easily found in the spindle cells. All renal cell carcinomas stained positive for CK, NKI/C3 staining was variable, and all were negative for HMB-45, HMB-50, smooth muscle actin (HHF-35), and calponin.nnnCONCLUSIONnIn renal angiomyolipoma, the epithelioid and spindle cells have preferential staining patterns for melanoma-associated antigens versus smooth muscle antigens, respectively. Positivity in renal angiomyolipoma for HMB-50, NKI/C3, and tyrosinase, in addition to HMB-45, provides evidence for the presence of different melanoma-associated gene products. Immunophenotypic overlap of the 3 histologically distinct renal angiomyolipoma cell populations suggests a common cell line, supporting a unitarian concept for renal angiomyolipoma. Ultrastructural characteristics of the 3 renal angiomyolipoma cell phenotypes parallel the immunophenotype, giving further support to a common cell line. Our study lends further credence to the perivascular epithelioid cell concept as proposed by Bonetti and colleagues.

Salivary Gland Neoplasia: A Review for the Practicing Pathologist

Epidemiology Over the years there has been some progress in clarifying specific causes of salivary gland cancer. The best known risk factor is that of radiation exposure as evident in the increased risk in atomic bomb survivors and in patients receiving therapeutic radiation. An increased occurrence in children with leukemias treated with multiagent chemotherapy and prophylactic cranial irradiation has also been noted (1). A dose response effect for low dose irradiation has been shown with a mean latency period of tumor development of 11 years for malignant tumors and 21.5 years for benign tumors (2). However, no increased risk is noted for exposure to UVB radiation. Of potential viral etiologies, only EBV infection is implicated in the pathogenesis of salivary lymphoepithelioma-like carcinomas that are more commonly encountered in Eskimo and Chinese rather than Western populations. However, no increased risk is documented for infections with herpes, papilloma or HIV viruses (3, 4). Contrary to one previous study (5), it is acknowledged now that there is no increased risk of a second primary breast cancer in women who have had previous salivary gland cancer. However, there is some increased risk for the development of second primary cancers of the oropharynx, thyroid gland and lung, especially for those whose salivary gland cancers were treated with radiotherapy (6). Unlike other head and neck cancers, alcohol and smoking abuse are not associated with increased risk for developing salivary gland neoplasms with the exception of a greatly increased risk and association of smoking with Warthin’s tumor (7–9). One interesting finding, unconfirmed by others, is an elevated risk of salivary gland cancer in women employed as hairdressers and those working in beauty salons (10).

The diagnostic utility of p63, CK5/6, CK 7, and CK 20 in distinguishing primary cutaneous adnexal neoplasms from metastatic carcinomas

Background:u2002 Distinguishing primary cutaneous adnexal neoplasms (PCANs) from metastatic carcinomas (MCs) can be difficult. We study the utility of p63, CK 5/6, CK 7, and 20 expression in PCAN vs. MC.

Common clonal origin of synchronous primary head and neck squamous cell carcinomas: Analysis by tumor karyotypes and fluorescence in situ hybridization

Two synchronously arising primary squamous cell carcinomas (SCC) originating from separate sites in the anterior floor of mouth (FOM) and the pyriform sinus (PS) were evaluated by karyotype and fluorescence in situ hybridization (FISH) to determine whether they were of common or independent ancestry. The primary tumors were designated Henry Ford Hospital (HFH)-SCC-8a (FOM) and HFH-SCC-9a (PS), and the respective recurrent tumors after chemotherapy and radiation were designated -8b and -9b. HFH-SCC-8a and -8b were cultured and had closely related hypotetraploid karyotypes of monoclonal origin. Karyotypes could not be obtained from the second primary tumor HFH-SCC-9a or its recurrence -9b. However, we used karyotypes from HFH-SCC-8a and -8b as a guide to select FISH probes for the histological evaluation of genetic markers in tumor sections. Fluorescence in situ hybridization on metaphase chromosomes from the cell cultures was useful in modifying the tumor karyotypes. Fluorescence in situ hybridization identified a chromosome Y rearrangement that was not obvious from the HFH-SCC-8a and -8b karyotypes, and this Y rearrangement served as a unique clonal marker. Using two probes for the Y chromosome we showed that all four tumors shared the same Y rearrangement with loss of Yq (DYZ1) and retention of Ycen (DYZ3). Furthermore, FISH showed that all four tumors had the same aneuploidy patterns for chromosomes X, Y, 7, 9, 15, 16, and 17. From karyotypic and FISH analysis disomy for X and 9 centromere regions and the rearranged Y were all predicted and observed in the tumor tissue sections. Tetrasomy and trisomy for 7, 15, 16, and 17 were predicted from the karyotypes and this also was observed using FISH in all four tumors. These FISH aneuploidy patterns and the presence of a clonal Y marker in all four tumor samples indicate that the synchronous primaries and their recurrences were of monoclonal origin.

A simplified laboratory validated assay for MGMT promoter hypermethylation analysis of glioma specimens from formalin-fixed paraffin-embedded tissue

Glioma, and in particular high-grade astrocytoma termed glioblastoma multiforme (GBM), is the most common primary tumor of the brain. Epigenetic silencing of the MGMT (O6-methylguanine-DNA Methyl transferase) DNA repair gene by promoter methylation compromises DNA repair and has been associated with longer survival in patients with GBM who receive alkylating agents. The methylation status of the MGMT promoter is determined by methylation-specific polymerase chain reaction analysis (MSP). This protocol is often challenging with GBM specimens, because of extensive necrosis and scarcity of malignant cells. The objective of this study was to develop a reliable, clinically validated assay for detection of epigenetic silencing of the MGMT gene using formalin-fixed, paraffin-embedded brain tumor resections and methylation-specific PCR.

Immunohistochemical study of melanocytic nevus and malignant melanoma with monoclonal antibodies against s-100 subunits

Immunohistochemical localization of S‐100 protein α and β subunits in the cells of melanocytic nevi and malignant melanomas was studied by using monoclonal antibodies directed against each subunit. Although polyclonal anti‐S‐100 reactivities have been demonstrated uniformly in all nevus cells and melanoma cells, monoclonal anti‐S‐100α and anti‐S‐100β reactivities were either absent or rarely found in ordinary junctional nevi or junctional nests of ordinary compound nevi. However, in the junctional nests of dysplastic junctional nevi and junctional components of dysplastic compound nevi, monoclonal anti‐S‐100α reactivity become more frequent, whereas monoclonal anti‐S‐100β reactivity remains negative. In the superficial variety of melanomas such as superficial spreading melanoma and lentigo maligna melanoma, monoclonal anti‐S‐100β is nonreactive until vertical growth or invasiveness begins. Most nodular melanomas are positively stained with both monoclonal anti‐S‐100α and anti‐S‐100β. It is suggested that monoclonal anti‐S‐100α can be an indicator of active junctional nevus of melanocytic nevi and the reactivity with monoclonal anti‐S‐100β may be related to vertical progression of superficial spreading melanomas and lentigo maligna melanomas.

Cutaneous verruciform xanthoma: a report of five cases investigating the etiology and nature of xanthomatous cells.

Verruciform xanthoma is a rare clinicopathologic entity of uncertain etiology that occurs primarily in the oral mucosa. Aggregates of foam cells in the submucosal stroma or papillary dermis in association with verrucous epithelial hyperplasia are the hallmark of this lesion. Extraoral (cutaneous) occurrence of verruciform xanthoma is much rarer and has been reported mostly in the genital skin. Five cases of extraoral cutaneous verruciform xanthoma (three from the scrotum, one from the penis, and one from the nose) and one histologic simulant (from skin of the nose) were studied. The lesions were solitary, raised, or polypoid with cup-shaped craters filled with parakeratotic cells that blended into keratinocytes of an acanthotic and papillomatous epidermis. There was a neutrophilic infiltrate of varying intensity between plump parakeratotic cells and keratinocytes, near the surface of the epidermis. Aggregates of foam cells were present in the papillary dermis, which was highly vascular. A plasma cell predominant infiltrate was seen at the base in a bandlike fashion. Despite the architectural resemblance of verruciform xanthoma to verrucous mucocutaneous lesions related to human papillomavirus infection, it was not detected by either immunohistochemistry, in situ hybridization, polymerase chain reaction, or Southern blot analysis in any case. The foam cells were weakly positive for cytokeratin and for Factor XIIIa but negative for S-100 protein. The KP1 and Mac 387 immunostain showed focal weak staining in foam cells. We postulate that a cascade of events pursue after initial keratinocytic damage attracting neutrophils, with subsequent phagocytosis of necrotic keratinocytic debris by dermal dendrocytes, eventually leading to the ultimate manifestation of the lesion as verruciform xanthoma. The etiologic agent remains elusive, but based on our findings, we conclude that verruciform xanthoma is most likely not a human papillomavirus-associated squamoproliferative lesion and that the foam cells, a histologic hallmark of the lesion, are most likely derived from dermal dendritic cells.

p16INK4a expression in actinic keratosis and Bowen's disease

Backgroundu2003 Progression of cutaneous squamous neoplasms from actinic keratosis (AK) to Bowens disease (BD; squamous cell carcinoma in situ) has important implications for clinical management and treatment, thus requiring accurate diagnosis. p16INK4a is a cell cycle regulatory tumour suppressor protein that negatively regulates D‐type cyclins in the G1 cell cycle phase via intimate interplay with the retinoblastoma gene. Expression of a paraffin‐reactive p16INK4a marker has recently been shown to increase in cervical squamous neoplasms as lesions progress from low‐grade dysplasia to squamous cell carcinoma in situ. p16INK4a expression in the progression of squamous cutaneous neoplasia, however, has not been evaluated.

Thymopharyngeal Duct Cyst: A Form of Cervical Thymus

A unique case of a cystic thymopharyngeal duct with coexistent thymus and parathyroid glands is presented as a rare form of cervical thymus. The embryology of normal cervical descent of the thymus is reviewed. Special attention is given to the pathogenesis of a wide variety of cervical thymic tissue which may be encountered. A unifying scheme and nosology are proposed for deciphering the various reported types of solid and cystic cervical thymic abnormalities.

A comparative immunohistochemical study of peritoneal and ovarian serous tumors, and mesotheliomas

The distinction between serous neoplasms of the peritoneum in women and conventional mesothelioma can be difficult. In order to determine any significant immunohistochemical differences, formalin-fixed, paraffin-embedded sections of 10 peritoneal serous tumors (PST), 10 ovarian serous tumors (OST), and 10 epithelial mesotheliomas were evaluated with a panel of 10 antibodies directed against carcinoembryonic antigen (CEA: polyclonal, monoclonal), high molecular weight keratin (34 beta E12), low molecular weight keratin (35 beta H11), Leu-M1, TAG-72 (monoclonal antibody B72.3), human milk fat globulin (HMFG-2), vimentin, placental alkaline phosphatase (PLAP), and S-100 protein. The antibodies CEA, Leu-M1, and B72.3 had the most discriminatory value in differentiating serous tumors from mesothelioma. Eighty-five percent of PSTs and OSTs (17 of 20) were positive with CEA, Leu-M1, and/or B72.3. None of the mesotheliomas stained for CEA or Leu-M1; three mesotheliomas had very focal positivity with B72.3 (1% or less). Vimentin, PLAP, HMGF-2, keratin, and S-100 had no significant discriminatory value. Epithelial mucin was present in 80% of serous tumors, while the mesotheliomas lacked epithelial mucin. Leu-M1, CEA, and/or B72.3 positivity in a peritoneal tumor supports a diagnosis of serous tumor. However, since some PST do not stain for any of the three antibodies and the focal nature of positive reactions in some cases may be difficult to interpret, exclusion of mesotheliomas is enhanced by the use of mucin stains.