An Adenoidal Cystic Carcinoma Arising from the Lacrimal Gland : A Report of Two Cases

An adenoidal cystic carcinoma (ACC) is well recognized for its characteristic pathological features. The majority of ACCs occur in the salivary glands of the neck and oral cavity but rarely in the orbita. Herein we report two cases of an ACC that arose from the lacrimal gland in which the clinical presentations were significantly different. The proliferative potential in both cases was estimated by an immunostaining method using the MIB-1 antibody. The first patient was a 63-year-old man who had suffered from headaches, double vision, and right proptosis for 2 months prior to his first hospital admission. CT scans demonstrated a defined, right lacrimal gland tumor which was resected subtotally, after which the patient was given irradiation. A histological examination showed the tubular structures of an ACC that were substantially accompanied by solid structures. Sixteen months later, however, an extensive intracranial invasion with a minimal local recurrence was discovered. Therefore, a second operation was performed and was followed by irradiation. Thus, local control was successfully achieved, though there was evidence of a small residual tumor. Pathological findings revealed the predominance of a solid pattern. The MIB-1 positive rate was ll.8%. There was a further recurrence 1 year later. The second patient was a 45-year-old man with a 2-month history of diplopia and the attenuation of optic acuity of the left eye. A radiological evaluation demonstrated the presence of a round mass in the left lacrimal gland. This mass was totally excised including the surrounding soft tissue, after which irradiation of 5,l00 cGy was given postoperatively. Inspection of a surgical specimen revealed a cribriform ACC with no other structures. MIB-1 immunostaining showed a positive rate of 6.8%. At 16 months postoperatively, the patient remains free of a recurrence. ACCs comprise about 10% of all salivary neoplasms and thus represent a definite clinicopathological entity. Although enlargement of this tumor is slow, a local recurrence is common and a metastasis can occur as life is prolonged, indicating its potentially malignant behavior. Previous reports and the results of MIB-1 immunostaining suggest that a solid pattern ACC can be more aggressive in both its clinical and pathological aspects than its tubular or cribriform subtypes. MIB-1 immunostaining is applicable even for paraffin-embedded tissue specimens and the procedure is recommended for achieving a prognosis. A wide excision including an adequate margin offers the best chance for cure with palliative radiotherapy given postoperatively to inhibita a recurrence.