Superficial papular neuroma: Case series of a new entity

A Case of Superficial Papular Neuroma: A Rare Neural Neoplasm

ABSTRACT

A case of 67-year-old male patient with superficial papular neuroma (SPN) on the occiput is reported. This is the second report of SPN and the first with clinical images. Histologically, in the superficial dermis and periadnexa, the specimen exhibits a nodule of bland spindle cells with an S-shaped and spindle nucleus, surrounded by eosinophilic collagen fibers and scattered mast cells, which forms focally peripheral nerve-like structures. Lichen simplex chronicus-like changes are observed. Immunostaining result revealed that the tumor cells are positive for S-100, neurofilament, collagen IV, and CD34 but negative for Melan A, epithelial membrane antigen, and glial fibrillary acidic protein. Histological differential diagnosis includes prurigo nodularis, neurotized nevus, benign peripheral nerve sheath tumor, such as neurofibroma or schwannoma, a type of neuroma, such as traumatic neuroma, mucosal neuroma, and palisaded encapsulated neuroma, or a type of neural hamartoma. A careful histological investigation will enable dermatopathologists to make a diagnosis of SPN.

Periadnexal Nerve Hyperplasia: A Reactive Histopathological Feature and an Incidental Finding After Surgical Excision and Scar Formation

Cutaneous nerve hyperplasia is characterized by the presence of increased and hypertrophic myelinated and unmyelinated nerve fibers in the dermis. We report a case of periadnexal nerve hyperplasia as an asymptomatic and infrequent reactive histopathological change, with no associated risk of malignancy that can be seen in scars, in patients with no syndromic stigmata.