29-31) It is detected in pathologic bladders, denoting squamoid
phenotype change of urothelium.
The tumor cells are poorly differentiated, yielding a polygonal, pleomorphic, spindle, giant, epithelioid, or squamoid
The relationship of the WHO classification and previous histologic classifications is as follows: type A corresponds to spindle cell type or medullary type thymoma; AB corresponds to mixed type; B1 corresponds to lymphocyte-rich type, lymphocytic type, predominantly cortical type, or organoid type; B2 corresponds to cortical type; B3 corresponds to epithelial type, squamoid
type, or atypical thymoma, or well-differentiated thymic carcinoma; and type C corresponds to thymic carcinoma.
Rarely, there were small collections of cells with a squamoid
appearance, composed of polygonal cells with abundant eosinophilic cytoplasm, well-delineated cell borders, and, focally, keratinization.
The final histologic diagnosis was a poorly differentiated thyroid carcinoma with squamoid
features and a minor component of conventional papillary carcinoma.
Adjacent to the malignant cells were a few well-demarcated nodules of small, bland, polyhedral squamoid
cells with focal duct formation (figures 1 and 4).
Note that the occasional microfollicles in this case tend to be lined by cells with a very flattened or squamoid
Upon further workup of 16 tumors initially diagnosed as squamous cell carcinomas that had EGFR/KRAS mutations, they found that 10 (63%) were adenosquamous carcinomas and 5 (31%) were poorly differentiated adenocarcinomas that morphologically mimicked squamous cell carcinomas (adenocarcinomas with squamoid
morphology); 1 case (6%) had no follow-up.
Pancreatoblastoma: optically clear nuclei in squamoid
corpuscles are rich in biotin.
Obviously, choice of the name of this tumor is less important as long as ACCCC is appropriately recognized among more common epidermal tumors with squamoid
and/or clear cell differentiation, such as squamous cell carcinoma, sebaceous carcinoma, trichilemmal carcinoma, or pilar tumors, to alert clinicians for potential aggressive growth.
13) Other findings include increased (>5 per high-power field) mitotic activity, comedonecrosis, micropapillary and squamoid
growth patterns, and fibrocellular desmoplasia.
12,17) Histologic patterns of the transformed areas range from a cribriform high-grade adenocarcinoma to solid carcinoma with squamoid