Superficial angiomyxomas with and without epithelial components. Report of 30 tumors in 28 patients.

This paper describes 30 uncommon dermal and subcutaneous angiomyxoid tumors in 28 patients whose ages ranged from 4 to 78 years (mean, 39 years). There were 16 male patients and 12 female patients. Tumor size varied from 0.5 to 9 cm, with the majority measuring 1-5 cm. Eleven tumors (37%) were located on the trunk, ten (33%) on the lower extremity, five (17%) on the head or neck, and four (13%) on the arm. Microscopically, there were moderately to sparsely cellular angiomyxoid nodules with scattered small vessels. Nine tumors had an epidermal component that took the form of a keratin-filled cyst or epithelial strands. The angiomyxoid components of all 30 tumors were morphologically similar. Electron microscopy showed fibroblastic stromal cells, proteoglycan matrix, and collagen fibers. The S-100 protein stain was negative in two tumors, and the vimentin stain was positive in stromal cells in one tumor. Follow-up information obtained for 20 of the 28 patients included data on eight tumors with epithelial components. Five (63%) of those eight tumors recurred once; three had not recurred, and one patient developed a new and separate purely angiomyxoid tumor. Three (23%) of 13 tumors without epithelial components recurred. None recurred more than once, and none metastasized. We suspect that superficial angiomyxoma, cutaneous focal mucinosis, trichogenic myxoma, trichogenic adnexal tumors, trichodiscoma, myxoid perifollicular fibromas, trichofolliculomas and fibrofolliculomas, the Carney complex, NAME and LAMB syndromes are all closely related. We also believe that the solitary superficial angiomyxoma with no epithelial elements is the most common manifestation of these myxoid tumors.