An atypical endocrine tumor of the lung responsive to radiation therapy and 5-fluorouracil-streptozotocin

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Abstract
A case is reported of a patient who presented with a peripheral left upper-lobe lung mass, a thyroid nodule, and multiple enlarged cervical and supraclavicular lymph nodes. Fine-needle aspiration cytology of the lung lesion, the thyroid nodule, and several of the lymph nodes was interpreted as small cell cancer of the lung (SCCL). The patient was treated with Cytoxan (cyclophosphamide), Adriamycin (doxorubicin), and vincristine (CAV), alternating with VP-16 + cisplatin. When progressive disease was documented after three cycles of chemotherapy, an involved cervical lymph node was biopsied. By light microscopy (LM) the tumor appeared to be a poorly differentiated adenocarcinoma, but by transmission electron microscopy (TEM) it was found to have both neuroendocrine and glandular features. Biochemical analysis of the biopsy specimen revealed immunoreactive bombesin, and on immunoperoxidase staining many tumor cells contained neuron-specific enolase. The tumor was therefore classified as an atypical endocrine tumor of the lung (AETL), a recently described morphologic variant for which no therapy has yet been established. The patient was treated with radiation therapy (RT) followed by chemotherapy including 5-fluorouracil (5-FU) (500 mg/m2 IV, d 1–5) and streptozotocin (STZ) (500 mg/m2 IV, d 1–5) every 5–6 weeks, with objective evidence of tumor regression following each modality. This report illustrates the importance of ultrastructural study in the characterization of lung cancer, and indicates the need for the further evaluation of RT and 5FU + STZ in the treatment of neuroendocrine tumors of the lung.