# Meningothelial Hamartoma Masquerading as a Lipoma: A Case Report and Review of Literature

## TL;DR

A rare scalp tumor called meningothelial hamartoma was mistaken for a lipoma, but was correctly diagnosed through surgery and lab tests.

## Contribution

This case highlights the importance of histopathology and immunohistochemistry in diagnosing meningothelial hamartoma.

## Key findings

- Meningothelial hamartoma was confirmed via histopathology and IHC markers like EMA and vimentin.
- The patient had no recurrence after surgical excision and one year of follow-up.
- The lesion was initially misdiagnosed as a lipoma based on MRI and FNAC.

## Abstract

Meningothelial hamartoma is a rare, benign scalp lesion that is often misdiagnosed as common soft tissue tumors such as lipomas. It is characterized by ectopic meningothelial elements and is classified as a type of cutaneous meningioma. Due to its rarity and histological overlap with other lesions, diagnosis requires histopathological examination and immunohistochemistry (IHC). A 36-year-old female presented with a painless, slow-growing lump on the left forehead persisting for 10 years. Magnetic resonance imaging (MRI) findings suggested a lipoma, and fine needle aspiration cytology (FNAC) indicated a fibro lipomatous lesion of neoplastic nature. It was surgically excised, and histopathology revealed mature adipose tissue with meningothelial cells. IHC showed epithelial membrane antigen (EMA) and vimentin positivity, confirming meningothelial hamartoma. The patient recovered well postoperatively, with no recurrence after one year. Meningothelial hamartoma is often misdiagnosed due to its resemblance to more common scalp tumors. Surgical excision is the mainstay of treatment, and IHC markers such as EMA and vimentin are essential for diagnosis. Given its potential hormonal influences and association with nevus sebaceous, further research is warranted. Clinicians should consider meningothelial hamartoma in atypical scalp lesions to ensure accurate diagnosis and appropriate management.