Eccrine Poroma Arising within Nevus Sebaceous

Abstract

Secondary neoplasms in nevus sebaceous can develop during adolescence and adulthood. Trichoblastoma and syringocystadenoma papilliferum are the most common benign neoplasms, but poroma is rarely reported. A 28-year-old female presented with an asymptomatic mass on the scalp. She has had a hairless lesion on the scalp since birth. A soft mass developed on that lesion four years prior. Physical examination revealed a localized 1 cm×2.5 cm-sized brownish, verrucous-surfaced plaque with a 1 cm×1 cm-sized pedunculated erythematous tumor on the scalp. We performed skin biopsy on both the plaque and tumor lesions. The histopathological findings demonstrated the plaque lesion consistent with nevus sebaceous and the tumor lesion consistent with eccrine poroma. Surgical mass excision was performed. The patient was eventually diagnosed with eccrine poroma arising within nevus sebaceous. To the best of our knowledge, there are only six reported cases on poroma arising within nevus sebaceous. Although rarely documented in the literature, it should be considered as a secondary neoplasm within nevus sebaceous.

A case of naevus sebaceus of Jadassohn of the scalp in Jamaica

“…NS has pluripotent potential [ 7 ]. A secondary tumour from a NS may differentiate into follicular, sebaceous, apocrine and eccrine cells and, rarely, a secondary tumour can differentiate into muscle [ 5 , 7 ]. The literature varies in the malignant transformation risk from 0.8–22% [ 3 ] Old reports overestimate the frequency of malignant tumours due to a misdiagnosis of basal cell carcinoma (BCC) for trichoblastomas [ 6 ].…”

Sebaceous nevus of Jadassohn: review and clinical-surgical approach

“…6,15 A linear nevus is usually reported in Schimmelpenning-Feuerstein-Mims syndrome and, as a component of multisystemic disorders, which have been previously described in a wide variety of organs, such as the nervous, ocular, cardiovascular, muscular, urogenital systems, and bones, among others. 14,15,22,23 Aiming to facilitate the identification and clinical diagnosis, Table 1 shows the main disorders that have been previously identified and related to Schimmelpenning-Feuerstein-Mims syndrome, among which the most frequently reported in the literature are: hypophosphatemic rickets, intellectual disability, and cognitive impairment, coloboma and strabismus. 5,11,22…”

“…2 In this regard, the main reported benign neoplasms are trichoblastoma (TB) and syringocystadenoma papilliferum (SCAP), followed by trichilemmoma, sebaceous adenoma, desmoplastic trichilemmoma, apocrine adenoma, and poroma. 2,18,23 Trichoblastoma is defined as a trichogenic tumor, formed by the proliferation of follicular germ cells. 16 On histological examination, trichoblastoma shows small cells of round to oval morphology, grouped and separated by a fibrous stroma, in a stratified squamous epithelium and areas of necrosis with calcification.…”

“…15,25 Table 2 below depicts the most recurrent neoplasms in medical literature associated with nevus sebaceous. 2,12,23…”