Primary Cutaneous Perivascular Epithelioid Cell Tumor: Not the Same as the Noncutaneous Tumor

Angelica Selim, MD reviewing Charli-Joseph Y et al. J Am Acad Dermatol 2014 Dec.

No local recurrences or metastases occurred in a series of eight tumors.

Perivascular epithelioid cell tumors (PEComas) affect internal organs and skin. Eight percent are primary cutaneous tumors (pcPEComas), dermal-based proliferations of clear cells. Originally categorized as myomelanocytic, pcPEComa is now included among perivascular tumors. However, the cell of origin is still elusive. These authors provide further insight.

They reviewed clinicopathologic and histologic features of eight pcPEComas. Tumors were more frequent among women, mean age 46 years. The most common clinical diagnosis was dermatofibroma. More than half of tumors affected lower extremities as indurated nodules. After complete excision and a mean follow-up period of 6.5 years, no local recurrences or metastases were detected. Tumors ranged in size from 4 to 20 mm and consisted of dermal clear cells with vesicular central nuclei arranged in thin aggregates, in strands, and singly, frequently extending to the subcutis as pushing nodules. There was no significant pleomorphism; mitotic rates were 0 to 2 per 10 HPF. Tumors were positive for MiTF-1, NKI-C3, bcl-1, CD68, and cathepsin K; 4E-binding protein 1 was seen in 90% of cases. SMA, desmin, p16, S-100 and HMB-45 showed low reactivity. CD56, keratin, and SOX10 were negative. KI-67 was a highlight of low-rate proliferation. No samples showed chromosomal imbalances. DNA sequencing showed wild-type BRAF, NRAS, KIT, GNAQ and GNA11.

Citation(s):

Charli-Joseph Y et al. Primary cutaneous perivascular epithelioid cell tumor: A clinicopathological and molecular reappraisal. J Am Acad Dermatol 2014 Dec; 71:1127.