Although smooth yellow nodules on the lip are typically considered benign, recent findings indicate they may, in rare instances, represent basal cell carcinoma.
A recent case series and literature review identified 4 instances of lip basal cell carcinoma (BCC) that presented as yellow nodules, a rare clinical appearance that may be mistaken for benign lesions such as lipomas or fibromas. These 4 cases were among 10 biopsy-confirmed lip BCCs diagnosed between 2000 and 2023 at a diagnostic oral pathology service in Canada. The study also included a literature review encompassing 27 previously reported cases.
BCC is the most common human malignancy and often occurs on sun-exposed areas of the head and neck. However, BCCs involving the lips are uncommon, particularly on the mucosal or vermilion surfaces, and may be misdiagnosed due to variable clinical presentations. Most lip BCCs are described as ulcerated, crusted, bleeding, eroded, or centrally depressed. In contrast, the 4 newly reported cases presented as smooth, yellow nodules with intact mucosal surfaces and no clinical suspicion of malignancy.
Among the 10 study cases, 6 exhibited classic features such as red, white, brown, crusted, bleeding, scabbing, eroded, or ulcerated lesions. The other 4 were considered non-classic and presented as smooth yellow lesions or submucosal nodules. One of these lesions persisted for 5 years before diagnosis. These non-classic tumors were located on or near the vermilion or labial mucosa. None of these 4 lesions showed surface ulceration on histologic examination.
Patients ranged in age from 49 to 88 years (mean, 68 years). Five lesions occurred on the upper lip and 5 on the lower lip. Histologically, 9 tumors were classified as nodular BCC, and 1 was fibroepithelial BCC. The tumors demonstrated characteristic features of BCC, including basaloid tumor cells with peripheral palisading and retraction artifacts. Some lesions showed additional findings that may relate to the yellow color, such as central keratinization, cholesterol clefts, calcifications, and sebaceous glands. However, no single histologic feature was consistently observed across all 4 yellow nodules.
According to Justin Bubola, DDS, of the Faculty of Dentistry at the University of Toronto and lead author of the study, “To the best of our knowledge, this is the first report of BCCs on the lips presenting as yellow nodules.” The authors noted that these tumors “posed a diagnostic challenge, as the clinical impression was of a benign mesenchymal tumour and not of a malignancy.”
The literature review identified 27 additional cases of lip BCC, with patient ages ranging from 21 to 91 years (mean, 63.9 years). Among these, 17 cases occurred in men and 10 in women. Seventeen lesions involved the lower lip and 10 involved the upper lip. Most were described clinically as ulcerated (n = 12), crusted (n = 9), eroded (n = 5), or bleeding (n = 4). Only 1 was described as centrally depressed.
Treatment across both the institutional and literature cases included surgical excision (n = 14), Mohs micrographic surgery (n = 7), wedge resection (n = 3), and radiation therapy (n = 1). Follow-up durations ranged from 1 month to 12 years (mean, 4.6 years), with no reported recurrences or metastases.
These findings suggest that BCC can present with non-classic clinical features, including as yellow nodules on the lip. Clinicians should consider BCC in the differential diagnosis of persistent lip lesions, even when they resemble benign conditions. Given the potential for mimicry, histopathologic confirmation via biopsy is essential for definitive diagnosis.
The authors declared no conflicts of interest. Ethics approval for the study was granted by the Research Ethics Board of the University of Toronto (Protocol #47899).
Source: BDJ
