The tubular variant of adenoid cystic carcinoma of the Bartholin's gland

The authors report two examples of the tubular variant of adenoid cystic carcinoma of the Bartholin's gland. Each occurred in young women (both aged 34 years) and presented with a painful indurated mass, clinically thought to be of inflammatory nature. On microscopic examination, the most distinctive feature was the haphazard proliferation of bland-appearing tubular structures often lined by two cell layers. A thin, periodic acid-Schiff-positive basement membrane immunoreactive for collagen IV surrounded the tubules, but hyaline globules were virtually absent. The inner cell layer was strongly and diffusely cytokeratin positive, whereas epithelial membrane antigen reactivity was seen only along the luminal borders. Focal positivity for S100 protein identified the peripheral myoepithelial cells, which were confirmed by electron microscopy. Focal perineural invasion was seen. The histologic, ultrastructural, and immunohistochemical features of these tumors are similar to those of the tubular variant of adenoid cystic carcinoma arising in major and minor salivary glands. In one of the cases, which was followed for 6 years, the tumor metastasized, despite the low histologic grade, and the patient died. Similarities and differences between the tubular, cribriform, and solid variants and other vulvar tumors are discussed.