Basaloid squamous carcinoma of the hypopharynx with an extensive spindle cell component exhibiting a pedunculated polypoid mass.

We report a case of basaloid squamous carcinoma of the hypopharynx with an extensive spindle cell component in an 82-year-old man. The tumor (4.0 x 2.5 x 2.2 cm) was a pedunculated polypoid mass that was attached to the left pyriform sinus. Histologically, most (70%) of the tumor was composed of malignant spindle cell proliferation, and the rest (30%) was basaloid squamous carcinoma. Some of the spindle cells were positive for cytokeratins. The preoperative histologic diagnosis was difficult because the endoscopic biopsy specimens showed only spindle cell proliferation. This is an unusual presentation of basaloid squamous carcinoma of the head and neck.

Basaloid squamous cell carcinoma of the esophagus with or without adenoid cystic features.

CONTEXT: Basaloid squamous cell carcinoma (BSCC) of the esophagus is a rare malignant tumor that morphologically could bear some resemblance to adenoid cystic carcinoma (ACC) originating from salivary glands. OBJECTIVE: The purpose of this study is to describe the histologic, immunohistochemical, and ultrastructural findings of BSCCs of the esophagus, with an emphasis on comparing tumors with or without adenoid cystic features. DESIGN: We reviewed 239 cases of primary esophageal carcinoma and detected 12 cases (5%) of BSCC. The light and electron microscopic findings and immunocytochemical localization of various antigens, including cytokeratins (AE1, AE3), carcinoembryonic antigen, epithelial membrane antigen, S100, smooth muscle actin, and p53, were examined in these BSCC cases. RESULTS: Histologically, all BSCCs were composed of solid lobules or nests of basaloid cells with well-demarcated outlines surrounded by a fibrous stroma. Seven of 12 tumors showed areas of ACC-like features, that is, cribriform-like pseudoglandular lumina formation and hyaline material surrounding the tumor nests, whereas the remaining 5 tumors were apparently pure basaloid carcinomas. These 2 groups of tumors were histologically and immunohistochemically identical in many aspects, namely, high-grade nuclei of the tumor cells with frequent mitoses, abundant comedo-type necrosis, focal areas of concomitant squamous differentiation, consistent immunoreactivity for cytokeratins, and poor or absent staining for S100 and smooth muscle actin. Ultrastructurally, the basaloid tumor cells exhibited relatively undifferentiated cellular characteristics and undeveloped cell organelles. CONCLUSION: Basaloid squamous cell carcinomas of the esophagus frequently have an intimate association with ACC-like patterns, but their histologic, immunocytochemical, and ultrastructural features correspond more to poorly differentiated squamous cell carcinoma than to salivary gland ACC. This distinction is important because genuine ACC is much less aggressive than BSCC.

Basaloid squamous carcinoma with collagenous spherules and crystalloids.

A case of basaloid squamous carcinoma with unusual spheruloid and crystalloid structures occurring in the left submandibular region of 45-year-old woman is described. The tumor displayed features typical of basaloid squamous carcinoma. In addition, there were numerous eosinophilic deposits of extracellular matrix, which reacted positively on periodic acid-Schiff staining. These deposits were arranged in lamellar concentric and radial patterns. Ultrastructurally, they were composed of extracellular matrix components rich in basement membrane substances. A few banded collagen fibers were found in some deposits. Basaloid squamous carcinoma is an aggressive variant of squamous cell carcinoma, with a predilection to the head and neck region, that needs to be distinguished from other tumors that may contain abundant deposits of basement membrane rich material, especially from adenoid cystic carcinoma.

Ultrastructural distinction of basaloid-squamous carcinoma and adenoid cystic carcinoma.

Basaloid-squamous carcinoma is a unique and infrequent variant of squamous cell carcinoma with a predilection for occurring in the upper aerodigestive tract. The cardinal diagnostic criteria are the presence of basaloid cells arranged in lobules or cords and a squamous component. Another feature that distinguishes basaloid-squamous carcinoma from conventional squamous cell carcinoma is the development of multiple foci of amorphous, eosinophilic, or mucinous materials among the basaloid tumor cells. It is this feature in basaloid-squamous carcinoma that causes confusion with adenoid cystic carcinoma, especially the solid variant of adenoid cystic carcinoma. To clarify the distinctive features of these two types of tumors, the ultrastructural findings in three basaloid-squamous carcinomas from the head and neck region were compared with three adenoid cystic carcinomas, one from the head and neck region and one each from trachea and bronchus. Widened intercellular spaces, tonofilaments, and replicated basal lamina were present in both types of tumor. However, the ultrastructural features of glandular differentiation were present only in adenoid cystic carcinoma, whereas the ultrastructural features of squamous cell differentiation were present only in basaloid-squamous carcinoma. The distinction between basaloid-squamous carcinoma and adenoid cystic carcinoma is important since basaloid-squamous carcinoma is a clinically aggressive, high-grade form of squamous cell carcinoma, generally with a worse prognosis than adenoid cystic carcinoma.

Coexpression of neuroendocrine markers and epithelial cytoskeletal proteins in bronchopulmonary neuroendocrine neoplasms.

Neuroendocrine (NE) neoplasms of the human bronchopulmonary tract were examined by electron microscopy, immunocytochemistry, and gel electrophoresis of cytoskeletal proteins from microdissected tissue samples. All samples (carcinoids, well-differentiated NE carcinoma, NE carcinomas of intermediate type, NE carcinomas of the small cell type) contained significant numbers of cells that immunostained for one or more of the following neuroendocrine markers tested: bombesin, calcitonin, ACTH, leu-enkephalin, gastrin, serotonin, somatostatin, alpha-melanocyte-stimulating hormone, vasoactive intestinal peptide, glucagon, insulin, substance P, and neuron-specific enolase. Electron microscopy revealed typical NE cell features, including variable abundant and frequently heterogeneous neurosecretory granules. Tumor cells contained filaments specifically stained with different conventional and monoclonal antibodies to cytokeratins and displayed punctate plasma membrane staining with antibodies to desmoplakins, in agreement with the electron microscopic demonstration of tonofilament bundles and desmosomes. Immunocytochemistry for NE markers and cytoskeletal proteins on consecutive sections revealed both cytokeratins and neuroendocrine substances in single cells. Using gel electrophoresis of cytoskeletal proteins of tissue regions extracted with high salt buffer and detergent, we could detect, in the tumors tested, appreciable amounts of cytokeratin polypeptides 8, 18, and 19, i.e., major cytokeratins also found in certain other lung carcinomas such as adenocarcinomas. Tumor cells were not significantly stained with antibodies to other intermediate filament proteins such as vimentin, desmin, glial filament protein, and neurofilament protein. The results show that NE substances can be synthesized in cells containing a typical epithelial cytoskeleton, i.e., cytokeratin filaments and desmosomes. These findings support the notion of an epithelial character of these tumors and appear in contrast with recent reports that neurofilaments are the only type of intermediate filaments present in carcinoids and other pulmonary NE tumors. These observations may have important implications for the histogenesis of NE carcinomas and for diagnostic pathology.

Discontinuity of the basement membrane in fibrosing basocellular carcinomas and basosquamous carcinomas of the skin: an immunohistochemical study with human laminin and type IV collagen antibodies.

Thirteen basocellular carcinomas (BCC) of different histologic types and 5 basosquamous carcinomas (BSC) of the skin were stained for laminin and type IV collagen with rabbit antibodies against the human basement membrane (BM) proteins, using an immunoperoxidase technique. The BM around the tumor aggregates contained both laminin and type IV collagen, and was continuous and distinct in all the nonfibrosing BCCs but indistinct or interrupted in the fibrosing BCCs and BSCs. The BM was not influenced by the focal adnexal differentiation of the BCC cells. The disintegrity of the BM in the fibrosing BCCs and BSCs may reflect some kind of disturbance in the interaction between the neoplastic epithelium and the connective tissue stroma, and be connected with the more aggressive nature of these tumors compared with ordinary BCCs. Thus local aggressive behavior seems to be accompanied by defects in the BM.

Metatypical carcinoma of the lower eyelid.

Metatypical (syn. basosquamous) carcinoma, a variant of basal cell carcinoma, is morphologically and biologically different from the types usually encountered: although metatypical carcinoma is morphologically different from squamous cell carcinoma, it metastasizes with nearly the same frequency.