A Solitary Lump on the Scalp: Case report
Now open: Certificate Course in Management of Covid-19 by Govt. Of Gujarat and PlexusMDKnow more...Now open: Certificate Course in Management of Covid-19 by Govt. Of Gujarat and PlexusMDKnow more...
A woman in her early 70s was referred for evaluation of a solitary, asymptomatic lump on her scalp. She was born with the lesion but noticed some growth following a minor local trauma a couple of months prior to seeking medical evaluation. Her medical history was unremarkable apart from an allegedly benign breast nodule resection in her teenage years.

Clinically, there was an ill-defined, infiltrated plaque with a normochromic, exophytic nodule on her scalp vertex measuring 4.2 × 3.8 cm. It had a waxy surface with irregular transverse furrows and overlying alopecia. Dermoscopic evaluation findings revealed a homogeneous yellow hue with no visible vascular or pigmented structures and absence of follicular ostia. The lesion was firm and mildly tender to the touch and seemed adherent to the underlying bone. There were no palpable lymph nodes. A brain MRI was performed for further elucidation, as well as a punch biopsy which demonstrated a nonenhancing tumor with sharp margins in the subcutaneous tissue of the scalp with no underlying bone or intracranial involvement.

Immunostaining was strongly positive for vimentin and epithelial membrane antigen (EMA), focally positive for progesterone receptor, and showed an estimated 1% positivity for Ki-67. The clinicopathologic correlation was compatible with the diagnosis of a cutaneous meningeal heterotopia (CMH). Cutaneous meningeal heterotopia is suspected when there is a congenital fibrotic plaque or nodule with overlying alopecia on the scalp or lumbosacral region.

Primary and metastatic neoplasms on the scalp are distinguished from CMH based on clinical and histopathologic features. Scalp metastases at birth are exceedingly rare and usually show rapid growth and distinct microscopic morphologic features with conspicuous cellular atypia.

Surgical resection with exiguous margins is curative for CMH. Imaging studies are recommended before invasive procedures to exclude the presence of a residual stalk connecting the lesion to the central nervous system and associated bone defects, which occur in a minority of cases. The patient in this case opted not to undergo surgical treatment after being informed of the diagnosis. The lesion remained stable and asymptomatic after a 6-month follow-up.

Source: https://jamanetwork.com/journals/jamadermatology/fullarticle/2771176