Plexiform Spitz Nevus

Abstract

In 1999, Spatz et al. reported the first 2 cases of a plexiform variant Spitz nevus. We describe another case of this variant on the upper thigh of a 10-year-old boy and discuss the differential diagnosis. Histologically, it comprised nodules of epithelioid cells with a plexiform arrangement distributed throughout the superficial and deep dermis. The cells had moderate eosinophilic cytoplasm with vesicular nuclei and prominent nucleoli. Intranuclear inclusions were present focally. The tumor nodules were embedded in a myxoid stroma with intratumoral and peritumoral inflammatory cells including both lymphocytes and eosinophils. There were occasional melanin-containing spindle-shaped cells. An intraepidermal component could not be assessed, since the lesion was ulcerated. The differential diagnosis includes both melanocytic and nonmelanocytic lesions exhibiting a plexiform pattern of growth as well as myxoid lesions.

Cutaneous plexiform lesions

“…First reported in 1999, plexiform Spitz nevus is a distinctive variant that, to the best of our knowledge, has been described in three patients 23,24 . The reported lesions have involved the lower leg of a 17‐year‐old boy, the back of a 52‐year‐old man and the upper thigh of a 10‐year‐old boy.…”

“…Although classically described in association with neural tumors [neurofibroma, schwannoma, neurothekeoma, perineurioma, palisaded encapsulated neuromas, mucosal neuromas, malignant peripheral nerve sheath tumor (MPNST) and granular cell tumor], this unique growth pattern has also been observed with other cutaneous lesions of melanocytic (plexiform spindle cell nevus, plexiform Spitz nevus, cellular blue nevus, plexiform congenital nevus and melanoma) and fibrohistiocytic (plexiform fibrohistiocytic tumor) origins, among others (Table 1). 1–36 …”

“…Histopathologically, this unique melanocytic tumor consists of multiple dermal lobules and nodules of enlarged spindle to epithelioid melanocytes with a plexiform arrangement 23,24 . The nodules and bundles of melanocytes are usually regularly spaced and of relatively similar small sizes and shapes.…”

A case of Spitz nevus with multiple satellite lesions

“…It usually appears as a solitary dome-shaped nodule on the face, head and neck, or the lower extremities. [1][2][3][4][5][6][7][8][9][10] The lesions are usually smaller than 1 cm in diameter. 11 Spitz nevi are classified into 4 types 12 : light-colored and soft, light-colored and hard, darkcolored, and multiple or agminated.…”

Cellular neurothekeoma with a plexiform morphology: a case report with a discussion of the plexiform lesions of the skin

“…Cellular neurothekeoma is a plexiform dermal lesion that has wide, confusing and important differential diagnoses. From a practical and pragmatic point of view, we divided the dermal lesions that may show a plexiform morphology pattern into melanocytic and non‐melanocytic 11,12 . The melanocytic lesions that can exhibit a plexiform pattern include melanoma, plexiform Spitz nevus, deep penetrating nevus, spindle cell nevus, cellular blue nevus and (rarely) plexiform congenital nevus.…”