Extraocular Sebaceous Carcinoma in Muir-Torre Syndrome.

Sir,

A 58-year-old male patient presented to our clinic with a small mass on the lower eyelid of the left eye which enlarged over a period of 2 years. Examination showed a nodular lesion of 3 mm × 4 mm in size in the middle of the lower eyelid. In addition, the patient had a pigmented nevus of 4 mm × 4 mm on the left cheek for 6 months. This macular lesion was characterized by ulcerations in the middle with increased telangiectasia on dermoscopy [Figure 1]. There was no similar lesion elsewhere in the body and no history of radiation exposure. There was no localized or generalized lymphadenopathy. The first lesion was excised under local anesthesia. The pathology report showed a basal cell carcinoma (BCC). According to this report, the lesion on the cheek is removed on the provisional diagnosis of BCC [Figure 2]. The immunohistological staining showed strong positivity for Ber-EP4 monoclonal antibodies, EMA (epithelial membrane antigen) antibodies, and CD15 antibodies. The pathologic analysis revealed a basaloid differentiation of sebaceous cells with a foamy cytoplasm [Figures 3 and 4]. The diagnosis of sebaceous carcinoma (SC) was made. The surgical margin of the tumor was clear; re-excision was not made. The patient's medical history was relevant for intermittent rectal bleeding and a family history of colon cancer. The patient was referred to the gastroenterology department for investigation of possible internal organ neoplasms that may be a feature of Muir–Torre syndrome (MTS). Colonoscopy studies revealed multiple colorectal polyps of different sizes. Biopsy was performed, and the result was tubulovillous adenoma with varying degrees of dysplasia. The six-month follow-up of the patient did not show signs of recurrence or appearance of similar lesions.

Figure 1

BCC on the lower eyelid

Figure 2

Sebaceous carcinoma on the left cheek

Figure 3

Irregular epithelial lobules associated with epidermal ulceration and sebaceous cells in the center. H&E × 40

Figure 4

Differentiated sebaceous cells showing a foamy cytoplasm. H&E × 100

SC is a malignant tumor derived from the adnexal epithelium of sebaceous glands. It is classified into ocular and extraocular types. Extraocular SCs (ESCs) are less aggressive and account for 25% of the cases and are usually found in the head and neck region.[1] Surgical excision of the tumor with 5–6 mm is the most used treatment method.[2] The recurrence rate can be as high as 30%. The overall survival rate at 5 and 10 years is 71.1% ± 1.5% and 45.9% ± 2.1%, respectively.[3]

The diagnosis of such tumors should raise the suspicion of MTS, which is a rare autosomal dominant cancer syndrome characterized by an association of sebaceous gland tumors and a minimum of one internal malignancy. Internal malignancy includes gastrointestinal (47%), genitourinary (21%), and breast (12%).[4] Mayo score is accepted as a risk score to determine the possibility of MTS. Our patient had a Mayo score of 2 (age younger than 60 and a family history of Lynch-related cancer), which indicates a sensitivity of 100% and specificity of 81% for predicting a germ-line mutation.[5] The patient was referred to genetics for the detection of underlying germ-line mismatch repair gene mutations.

Regarding our case, the diagnosis of extraocular carcinoma was the key for early detection of premalignant colonic polyps before the transition to colonic cancer. It is necessary to be aware of the possibility of MTS whenever a SC is diagnosed. Internal malignancies within this syndrome may appear before or after the diagnosis of SC; thus, lifelong follow-up for internal organ neoplasms is required.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.