BCC or Not BCC? - A Case Report of Trichilemmal Carcinoma: A Rare Adnexal Neoplasm
Introduction
We present a case of trichilemmal carcinoma (TLC) in a 93yr old lady with a number of co-morbidities. Trichilemmal carcinoma is a rare type of adnexal neoplasm that arises from the folliculosebaceous apparatus and may be clinically misdiagnosed as basal cell carcinoma (BCC) or squamous cell carcinoma (SCC) as its appearance may be similar. However, TLC behaves in a more aggressive fashion with greater potential for local invasion and recurrence. It favours sun-damaged, hair-bearing areas such as the face, with the associated challenges of excision. The surgical treatment of skin cancers in the head and neck is being found more commonly under the discipline of oral and maxillofacial surgery so familiarity with its variants is important for its surgeons.
Diagnosis
The initial working diagnosis was nodular BCC of the left nasolabial fold with radiotherapy treatment proposed. BCC may be managed conservatively or with radiotherapy in older patients with multiple co-morbidities who are not suitable for surgery, but evaluation of the punch biopsy showed features suspicious for a malignant adnexal tumour and so excision with clear margins was recommended.
Management
The 15x20mm lesion extended over the left alar, upper nares and cheek. In view of the initial histology, it was completely excised and reconstructed with a pedical island flap and VY closure with satisfactory cosmetic effect.
Conclusions/clinical relevance
Trichilemmal carcinoma is a rare type of adnexal neoplasm, that may be misdiagnosed as BCC, but because of its more aggressive growth pattern correct identification and management is essential to avoid future complications. BCC may be managed conservatively or with radiotherapy in older patients with multiple co-morbidities who are not suitable for surgery, but TLC has not been shown to be amenable to adjuvant therapy so surgical treatment is required. As surgical treatment of facial skin malignancies becomes more common as part of the oral and maxillofacial remit, familiarity with the variations of lesion is desirable.
References
Crowson, Magro and Mihm, Malignant Adnexal Neoplasms, Modern Pathology (2006) 19, S93–S126
Wong and Suster, Tricholemmal carcinoma. A clinicopathologic study of 13 cases, Am J Dermatopathol. (1994) Oct;16(5):463-73.