The role of Mohs surgery in the management of benign sebaceous neoplasms

Abstract

Sebaceoma is a benign sebaceous neoplasm with rare potential for malignant transformation. We report a case of recurrent sebaceoma in a 70-year-old male with Muir–Torre syndrome, successfully treated with Mohs micrographic surgery. Despite its benign histology, the lesion demonstrated rapid growth and incomplete initial excision. Mohs micrographic surgery provided complete margin control with tissue preservation. This case highlights the value of Mohs micrographic surgery in managing select benign sebaceous neoplasms exhibiting concerning clinical behavior or diagnostic uncertainty, supporting its inclusion in treatment considerations for high-risk patients.

Introduction

Sebaceous neoplasms encompass a spectrum of lesions ranging from benign tumors such as sebaceous hyperplasia, sebaceous adenoma, and sebaceoma, to malignant entities like sebaceous carcinoma. ¹ Sebaceoma and sebaceous adenoma are primarily distinguished by the proportion of basaloid cells to mature sebocytes, with a >50% predominance of basaloid cells favoring a diagnosis of sebaceoma. ¹ Differentiating these benign entities from sebaceous carcinoma, however, relies on histological features and criteria that remain somewhat subjective and lack clearly defined guidelines. ¹ Although benign, sebaceoma can rarely transform to sebaceous carcinoma, arise concurrently with it in a benign nevus, or recur as sebaceous carcinoma at the site of prior complete excision.^1,2

Surgical excision remains the mainstay of treatment for sebaceous neoplasms to achieve definitive diagnosis and to ensure complete removal. ² While historically recommended to treat malignant tumors, Mohs micrographic surgery (MMS) has also been increasingly utilized for the treatment of benign tumors which demonstrate certain features such as aggressive clinical behavior, poorly defined clinical borders, incomplete primary excision, recurrence, or histopathological ambiguity. ³

Herein, we present a case of sebaceoma in a 70-year-old male with Muir–Torre syndrome (MTS), successfully treated with MMS. This case underscores the importance of optimal margin-control surgical management in sebaceoma that exhibit concerning features and supports the use of more aggressive treatment in select cases, given the tumor’s potential for malignant transformation or coexistence with sebaceous carcinoma.

Case presentation

A 70-year-old male with a medical history of multiple MTS-associated nonmelanoma skin cancer and sebaceous neoplasms. The patient was also previously treated twice for two distinct regional metastatic sebaceous carcinomas in 2013 and 2017. In October 2024, he developed a firm, white, verrucous nodule with a red rim on the left flank. The lesion had developed rapidly over a few weeks without pain or bleeding. The lesion’s morphology, rapid growth, along with the patient’s known diagnosis of MTS raised suspicion for a sebaceous neoplasm or keratoacanthoma. An excisional shave biopsy was performed, and histopathological assessment confirmed the diagnosis of sebaceoma with incomplete excision (Figure 1(a) and (b)).

Figure 1.

(a) Low power; (b) High power. Well-circumscribed, noninfiltrative lesion composed predominantly of basaloid cells (>50% of the tumor), lacking significant atypia or increased mitotic activity, with a minor component of clear cells exhibiting multivacuolated cytoplasm consistent with mature sebaceous differentiation.

The patient experienced regrowth of a cystic papule on the same location over the following 4 weeks. Clinical re-evaluation was concerning for recurrent growth of the sebaceous neoplasm. Given the patient’s genetic risk, incomplete initial excision, and fast local growth, and risk of the histological resemblance that sebaceoma can exhibit to sebaceous carcinoma, MMS was planned.

On November 27, 2024, the patient underwent MMS with complete histological clearance after a single Mohs stage and a defect size of 30.2 mm, 22 mm depth, and a two-layer primary linear closure.

At a follow-up 4 months later, no signs of recurrence or complications were noted.

Discussion

While MMS is traditionally used for the management of malignant cutaneous neoplasms, its role in treating select benign tumors under specific clinical circumstances is increasingly recognized. ³ Indications for MMS in benign lesions include involvement of cosmetically or functionally sensitive areas, histologic ambiguity, potential for malignant transformation, poorly defined clinical margins, recurrence, or prior incomplete excision. ³ Although MMS is widely accepted for treating malignant sebaceous neoplasms, its application in the management of benign sebaceous tumors remains less supported in existing guidelines. ⁴

Sebaceoma is generally considered a benign tumor. ¹ However, the literature has documented its coexistence with sebaceous carcinoma in nevus sebaceous of Jadassohn. ² Additionally, sebaceous carcinoma has been reported to arise at the site of previously treated sebaceoma. ¹ More recently, Daruish et al. described a case of malignant transformation in which a sebaceoma acted as a precursor lesion, evolving into a clinically evident sebaceous carcinoma confirmed via p53 immunostaining. ¹

The distinction between sebaceoma and sebaceous carcinoma relies on histopathologic criteria that are often subject to interpretation. ¹ Key features include cytologic atypia, atypical mitotic figures, pagetoid spread, nuclear polymorphism, and infiltrative growth patterns. ¹ Immunohistochemical staining is a valuable tool to support the diagnosis of sebaceous carcinoma in equivocal cases. ¹

In our patient, MMS provided successful margin-controlled treatment of a lesion that, while histologically benign, demonstrated worrisome clinical behavior. MMS was preferred over wide local excision (WLE) to aid in complete margin assessment, given the prior incomplete excision, minimize tissue loss and provide a more conservative approach in an MTS patient with higher morbidity from multiple cutaneous tumors and their associated treatments.

While both MMS and WLE are considered standard treatment options for sebaceous carcinoma, a systematic review of 70 studies reported lower recurrence rates with MMS. ⁴ More recent studies, however, have shown no significant difference in overall mortality between the two modalities, although a lower rate of disease-specific mortality was noted in patients treated with MMS.^4,5

We believe that MMS or WLE should be considered as primary treatment options for sebaceomas that are recurrent, display worrisome clinical features, or present with histologic ambiguity. This case contributes to the growing evidence supporting the expanded role of MMS in managing select benign neoplasms, particularly in high-risk populations. Future updates to appropriate use criteria may benefit from integrating risk stratification for benign lesions with malignant potential, helping clinicians make informed and individualized treatment decisions.