Contributor: Gordon K. Klintworth
Adenoid cystic carcinoma is a malignant neoplasm of lacrimal gland [adenoid cystic carcinoma - lacrimal gland] or salivary gland. This carcinoma is characterized by anastomosing cords of small cells with hyperchromatic nuclei and sparse cytoplasm. This tumor has cribriform, sclerosing, basaloid, comedocarcinoma and tubular histopathologic subtypes. The cribiform variety contains anastomosing cords of cells with hyperchromatic nuclei and sparse cytoplasm within a hyalinized or hypocellular fibrous stroma. Multiple cytic spaces perforate the cords and produce a pattern that has been likened to swiss-cheese. The basaloid adenocystic carcinoma consists of solid lobules or small nests of densely compacted cells with scant cytoplasm and rare lumens. This variant of the tumor can be mistaken for orbital invasion by a basal cell carcinoma, especially since adenoid cystic carcinoma can invade the eyelid and orbit. The differential diagnosis of adenoid cystic carcinoma includes basaloid squamous cell carcinoma [carcinoma - basaloid squamous cell].