Atypical histopathologic features in a melanocytic nevus after cryotherapy and pregnancy

Abstract

Melanocytic nevi can undergo clinical and histopathologic changes during pregnancy, as well as after various forms of surgical and nonsurgical trauma. We report the case of a 9-month postpartum 29-year-old female who presented to her dermatologist with a clinically worrisome nevus. This nevus had been treated with liquid nitrogen by her primary care physician 6 months prior to presentation. Histopathologic evaluation revealed a crowded proliferation of atypical melanocytes at the dermal-epidermal junction overlying a scar. The dermal component contained scattered mitotic figures. A combined MART-1, tyrosinase and Ki-67 immunohistochemical study showed foci of increased melanocytic proliferation. These atypical features were interpreted as associated with both the prior cryotherapy, as well as her recent pregnancy. Knowledge of the clinical context in evaluating difficult melanocytic lesions is essential.

Melanoma mimicking Rosai‐Dorfman disease

“…A case report of two nevi treated with cryotherapy showed histopathologic changes, including loss of the rete ridges, focal pagetosis, dermal fibrosis, loss of maturation by cell size, loss of the Ki67 gradient (although Ki67 expression was low overall) and aberrant expression of HMB‐45 in the dermal component . Another case of a frozen nevus in a pregnant woman showed similar fibrosis and focal pagetosis; however, there was increased proliferation of melanocytes, thought to be pregnancy related, as well as retention of MART‐1 staining . Our case did not show focal pagetosis but did show areas of fibrosis.…”

A Comparative Evaluation of Surgical, Electrosurgery and Diode Laser in the Management of Maxillofacial Nevus

“…It is generally accepted that all nevi should be submitted for histological examination for medicolegal reasons. In a recent study, 2.3% of clinically diagnosed benign nevi were microscopically diagnosed as malignant tumours, either melanomas or basal or squamous cell carcinomas [10][11][12].…”

“…Chemical peels, cryotherapy [12][13][14][15][16] and electrosurgery have obtained good cosmetic outcome but cryotherapy and electrosurgery show few disadvantages causing hypopigmentation of the treated skin and increasing the risk of malignant transformation.…”