Chondroid syringoma (mixed tumor) is a rare benign sweat gland tumor that commonly arises on the head and neck 1. Recurrence is rare and typically results from incomplete excision 1. The standard treatment is surgical excision, but literature describing the use of Mohs micrographic surgery (MMS) for chondroid syringomas, particularly on the lip, a site of both functional and aesthetic significance, is limited 2. We present a recurrent branching alveolar subtype of chondroid syringoma on the upper lip successfully treated with MMS and crescentic advancement flap reconstruction, representing, to our knowledge, the first such report. A 39-year-old female with Fitzpatrick skin type V presented for MMS of a recurrent cutaneous chondroid syringoma on the right upper cutaneous lip. Seven months prior, she had noticed a small bump that was excised 3 months later, confirming chondroid syringoma. The lesion regrew within 2 months at the same site, prompting evaluation with our team. Examination revealed a firm, well-circumscribed, smooth, pink papule measuring 0.6 × 0.5 cm on the right upper cutaneous lip, inferolateral to the nasal ala and medial to the melolabial fold (Figure 1a). Given the recurrence, aesthetic location, and potential for subclinical extension, MMS was performed to ensure complete margin control. The clinically visible tumor was first debulked, and a microscopic-controlled layer with a 0.1-mm peripheral margin was taken. Frozen sections were processed en face with complete margin evaluation and showed a well-circumscribed, multinodular dermal tumor composed of epithelial and myoepithelial cells embedded in a chondromyxoid stroma (Figure 2a). The epithelial cells were arranged in ductal structures, surrounded by a dense eosinophilic matrix. The first Mohs stage (1.3 × 1.2 cm) revealed invasion into subcutaneous fat with persistent nodular growth but no mitotic activity or cytologic atypia (Figure 2b). A second stage was taken in a similar fashion with a 0.1-mm margin and en face frozen section processing, which revealed limited extension into muscle. All margins were cleared at this stage, resulting in a final defect of 1.4 × 1.3 cm. Because of the proximity to the vermillion border and minimal skin laxity, a crescentic advancement flap extending to the vermilion was designed to hide suture lines (Figure 1b). At 1-week follow-up, the wound was well healed with an excellent cosmetic outcome (Figure 1c). Fewer than 50 facial cases of benign chondroid syringoma have been documented, with most treated by wide local excision 2. In rare instances, MMS has been employed for lesions involving the brow, cheek, and nasal dorsum 2, 3. One prior case involved the upper lip, although it did not represent a recurrent or branching alveolar subtype 4. Histologically, our case demonstrated the branching alveolar pattern, characterized by complex ductal structures within a chondromyxoid stroma, which to our knowledge has not previously been treated with MMS. Reconstruction of the upper lip requires meticulous restoration of both form and function. While linear closures may be appropriate in some cases, flap-based techniques are often beneficial in preventing contour and free margin distortion, especially in patients with minimal redundant skin. In this case, the crescentic advancement flap provided a tension-free closure that maintained philtral alignment and preserved vermilion definition without blunting the nasolabial fold or distorting the oral commissure. Although alternatives such as V-Y advancement flap could be considered, this technique carries a higher risk of pincushioning and creates horizontal linear scars, which are less easily concealed than vertical scars that align with natural perioral wrinkles, making it a suboptimal choice in this delicate region 5. This case highlights the value of MMS for recurrent, histologically benign but locally invasive tumors in cosmetically sensitive areas to achieve optimal aesthetic and functional outcomes through individualized reconstructive planning. The authors have nothing to report. This article did not require IRB approval as it involves no experimental interventions or investigations beyond standard clinical practice. Patient consent was obtained for publication. Dr. Tolkachjov is an investigator and speaker for CASTLE Biosciences, Kerecis, Boehringer Ingelheim, and Regeneron. No relevant conflicts of interest. The other authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.
Cho et al. (Fri,) studied this question.