Basal Cell Carcinoma Associated with Secondary Localized Cutaneous Amyloid Deposits: Case Report and Review.

Amyloid deposition has been observed in tissue specimens of basal cell carcinomas. A 68-year-old man with a nodular basal cell carcinoma on his left arm near the elbow is described; microscopic evaluation of the biopsy tissue specimen shows not only nodular aggregates and strands of atypical basaloid tumor cells but also marked deposition of amorphous amyloid material in the stroma between the aggregates of basal cell carcinoma. Including the man in this report, there are additional individual descriptions of patients whose basal cell carcinomas have amyloid deposits in the adjacent stroma or within the tumor aggregates or both. In addition, several retrospective pathology investigations have evaluated the features of this phenomenon. The incidence of basal cell carcinoma with amyloid deposition, in the English literature, ranges from 11% to 75%; however, it is possible that staining technique or tumor subtype or quantity of amyloid present may account for the lower detection of amyloid observed by some of the researchers. Amyloid in basal cell carcinoma specimens was observed to be present more frequently in older patients who had tumors with less aggressive histology patterns. Nodular basal cell carcinoma was the most common subtype of tumor with amyloid deposits whereas superficial basal cell carcinoma was the least frequent subtype. The amyloid deposits were usually identified on hematoxylin and eosin-stained sections and confirmed by using stains that allowed for easier visualization of the amyloid. The amyloid deposits were most commonly located in the stroma between the tumor aggregates; other locations included the papillary dermis above the carcinoma, the dermis at the advancing edge of the tumor and within the aggregates of basal cell carcinoma. Many of the basal cell carcinomas with amyloid deposits, similar to the reported patient, also contained solar elastosis. The origin of the amyloid deposition in these tumors is secondary amyloid AA protein from keratin derived from the epithelial cells overlying the basal cell carcinomas. The presence of amyloid deposition does not alter the management of these basal cell carcinomas; the treatment of the tumor is the same as when the basal cell carcinoma does not contain amyloid deposition.