Total Blindness as the Presenting Sign of Small Cell Lung Cancer

Abstract

Abstract: : Purpose:Metastatic disease to the pituitary gland is found in at least 2% of patients with a systemic malignancy at autopsy¹, although many of these patients have no visual symptoms. Malignant tumors may metastasize to existing macroadenomas, present as pituitary apoplexy, or remain silent. Visual loss from metastatic disease without a known primary is rare, and is typically associated with a previously–diagnosed systemic malignancy. Methods:Retrospective case review Results:A 32–year old male developed painless bilateral visual loss to no light perception over two days. His extraocular movements were full, and his anterior segment was within normal limits. A CT scan revealed a sellar mass, and a subsequent MRI confirmed the presence of suprasellar extension and chiasmal compression. Nonetheless, the patient did not have diabetes insipidus or hypopituitarism. At the time of craniotomy, histologic evaluation of the 2.5 x 2.0 x 0.8 cm lesion demonstrated small cell carcinoma. Subsequent CT of the chest revealed right hilar and subcarinal masses. After resection of the tumor, the patient underwent conformal radiation therapy to his pituitary and systemic chemotherapy. Despite the development of bilateral optic atrophy, he recovered a small island of 20/25 vision in his right eye. Conclusions:Visual loss from pituitary metastasis of an occult malignancy is very rare. Radiographic differentiation of pituitary macroadenoma from metastatic disease is often not possible in the absence of a known primary malignancy, although metastatic disease is more commonly associated with diabetes insipidus, anterior hypopituitarism, later age of onset, diplopia, and progressive cranial neuropathy. Nonetheless, our patient did not fit these characteristics. Clinicians should thus be aware that small cell lung cancer can metastasize to the pituitary, and should consider metastasis in the differential diagnosis of rapid visual loss from an atypical pituitary mass. ¹Lau, G, Tan, SY, Chiang, G, et al. Bronchoalveolar carcinoma with metastasis to the pituitary gland: a case report. Journal of Clinical Pathology. 51(12): 931–4. 1998.

Keywords: neuro–ophthalmology: diagnosis • oncology • visual impairment: neuro–ophthalmological disease