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Editor,—Sebaceous carcinoma is a rare primary neoplasm of the lacrimal gland and to the best of our knowledge only five cases have previously been reported.1-5 Sebaceous carcinoma of the orbit more commonly occurs as secondary invasion from the eyelid but may occur as metastatic spread from elsewhere in the body. We report a case of primary sebaceous carcinoma of the lacrimal gland and discuss the histological diagnosis and management of the disease.
A 35 year old woman was referred with a 6 month history of a gradually enlarging palpable mass arising in the left superotemporal orbit and causing painless, and progressive diplopia. On examination she had a palpable, hard, fixed, left superotemporal orbital mass, a non-axial proptosis, and hypoglobus. The eyelids were normal. Examination of ocular motility revealed a restriction of left elevation. In addition, she was found to have an enlarged, painless ipsilateral preauricular lymph node. Computed tomograph (CT) and magnetic resonance imaging (MRI) scans showed the mass was arising from the lacrimal gland (Fig1).
A transseptal biopsy of the mass was performed and histological examination showed tissue infiltrated by carcinoma in which the neoplastic cells were large and contained prominent nucleoli. Many cells were vacuolated and contained lipid as confirmed by fat stains on unprocessed, fixed material. Immunohistochemistry revealed strongly positive staining for epithelial membrane antigen (EMA) but negative staining with anticytokeratin, indicating the carcinoma to be of sebaceous origin (Fig 2). Metastatic spread from another primary site was excluded by general physical examination, chestx ray, mammography, and isotopic bone scan undertaken by an oncologist.
A left orbital exenteration with left superficial parotidectomy and excision of left cervical lymph nodes was performed. Histological examination of the exenteration specimen showed a 35 × 30 × 18 mm tumour arising in the region of the lacrimal gland, which had been entirely replaced by sebaceous carcinoma, with only a small focus of ductal tissue being present at the margin of the tumour at one point. There was no involvement of the overlying periorbital skin, eyelid, or conjunctiva. The preauricular lymph node contained metastatic deposits, although her cervical lymph nodes were free from metastatic disease.
Postoperatively she underwent radiotherapy to the involved area and the orbit was allowed to granulate and re-epithelialise. Nine months after the surgery an isolated soft, mobile node was noted in the neck. This increased in size over 2 months and was found to be recurrent metastatic carcinoma on fine needle aspiration biopsy. Radical dissection of nodes in the neck confirmed involvement of 30–40 nodes and the patient received further radiotherapy. Six months after this, a swelling in the parotid region without lymphadenopathy again showed recurrent tumour. This lesion responded well to radiotherapy alone. Since then she has achieved good cosmesis with an orbital prosthesis and at the time of writing 3 years after original diagnosis she remains well with no signs of residual tumour.
Primary sebaceous carcinoma of the lacrimal gland possibly arising from heterotopic sebaceous tissue is extremely rare and must be differentiated from secondary invasion of the orbit by a primary eyelid tumour or metastatic spread from other areas of the body. The tumour is highly malignant and metastases to the preauricular and deep cervical lymph nodes occur early in the disease. Orbital exenteration is required and in addition parotidectomy and cervical lymphadenectomy combined with postoperative radiotherapy should be considered as part of the management. The prognosis in previously reported patients was poor with local recurrences and metastases leading to death within 1 year. One previous patient survived to 22 months postoperatively.2 At the time of writing our patient is the first to show 3 year survival without evidence of further recurrence.