Paraganglioma-like dermal melanocytic tumor: a case report

Abstract

Paraganglioma-like dermal melanocytic tumor is a rare subtype of benign dermal melanocytic tumors. Its histopathologic features resemble those of paraganglioma, but the immunostaining characteristics are those of melanocytic lesions.We report a case of a 60-year-old male with a paraganglioma-like dermal melanocytic tumor of his left cheek and briefly review the English literature. Case presentationA 60-year-old male presented with a skin-colored slightly raised soft 0.8 cm papule on his left cheek present for an unknown period of time. The clinical impression was a "skin tag". The patient's past medical history was unremarkable. An excisional biopsy of the lesion showed a well demarcated cellular nodule in the dermis ( Fig. 1) with normal overlying epidermis. The neoplasm was composed of organoid and nested groups of large epithelioid cells separated by delicate fibrous strands and prominent blood vessels. The epithelioid cells had distinct large nuclei with prominent red nucleoli and somewhat clear cytoplasm (Fig. 2). Some of the large epitheliod cells had multiple nuclei and vacuoles. There was no cytoplasmic melanin pigment or eosinophilic granule. Neither mitotic activity nor necrosis was seen. There was one area of the tumor showing nests of mature nevus cells.

Paraganglioma-like dermal melanocytic tumor

“…The lesion may be confused with other benign dermal tumors such as cellular blue nevus, schwannoma, granular cell tumor or malignant lesions like melanoma and clear cell sarcoma. [ 2 ] But histopathological and immunohistochemical analysis helps to clinch the diagnosis. Two important microscopic features were present in all cases described until now:[ 3 ] (i) no evidences of melanocytic atypia or epidermal hyperplasia in the overlying epithelium; (ii) presence of a distinctive partitioning of the tumor into small and large packets, nests, or short cords by delicate fibrous septa (zellballen pattern).…”

“…[ 1 4 ] There is no necrosis but increased mitotic activity can be rarely encountered. [ 2 ] These histopathologic features are reminiscent of those of paraganglioma but tumor cells of paraganglioma are usually negative for melanocytic markers. Other malignant and potentially malignant dermal tumors, such as melanoma and dermal melanocytic tumor of uncertain potential can be excluded because of the absence of any atypical features, such as nuclear atypia, macronucleoli, increased mitotic activity, and necrosis.…”

“…The term was based on their nested growth pattern in histology, which shows nests of clear to amphophilic oval cells separated by delicate fibrous strands. [ 1 2 ] Only 10 cases have been reported so far and to the best of our knowledge none in dermatology journals.…”

Spindle cell melanocytic lesions: part II—an approach to intradermal proliferations and horizontally oriented lesions

“…Paraganglioma-like dermal melanocytic tumour is a newly defined melanocytic tumour confined to the dermis as a discrete, relatively well circumscribed nodule comprised of nests of melanocytes surrounded by delicate fibrous septa and a capillary network, reminiscent of paraganglioma 14 59 60. Most reported cases have occurred in young adult women, and mainly on the extremities.…”

“…Most reported cases have occurred in young adult women, and mainly on the extremities. The clinical course to date is universally favourable 59 60. The melanocytes are typically large amelanotic or lightly pigmented, epithelioid and/or spindled cells with abundant clear or eosinophilic cytoplasm.…”