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. Ann Diagn Pathol 5: 233-239, 2001.