Cytodiagnostic aspects of bronchioloalveolar carcinoma manifesting with small cell morphology on respiratory specimens: a case report.

Background: Exfoliation of bronchioloalveolar carcinoma (BAC) cells with small cell morphology in respiratory specimens can cause a diagnostic dilemma, particularly in patients with a history of bronchorrhea.

Case: A 59-year-old man presented with cough, breathlessness, and bronchorrhea. Clinically, he was diagnosed to have right-sided pulmonary consolidation. His sputum and bronchial washing specimens examined on multiple occasions revealed a varied number of single and loose aggregates of atypical cells, along with rare micropapillary and glandlike structures. The cells were small, round, and fairly monomorphic with a high nucleus to cytoplasm ratio and scant to moderate cytoplasm. Chromatin was uniformly distributed, with no appreciable nucleoli. At places, a vague nuclear molding was noted. Clinically, bronchorrhea and the diffuse infiltrative nature of the lesion favored BAC. Cytologically, prominent small cell morphology and nuclear molding suggested a possibility of small cell neuroendocrine tumor. However, careful cytologic examination of subsequent respiratory samples and biopsy revealed features of a nonmucinous type of BAC.

Conclusion: Despite the small cell morphology of neoplastic cells on exfoliative respiratory cytology, a clinical history of bronchorrhea should prompt a cytodiagnosis of BAC. A glandlike arrangement of cells and greater amount of cytoplasm should also assist avoiding misinterpretation in such instances.