Idiopathic diffuse hyperplasia of pulmonary neuroendocrine cells in a patient with acromegaly.

Idiopathic diffuse hyperplasia of pulmonary neuroendocrine cells (IDHPNC) is a rare disorder that most often presents clinically as obliterative bronchiolitis, but has also been associated with ectopic corticotropin syndrome. We describe a 49-year-old lifetime non-smoking female with longstanding cough, progressive exertional dyspnoea, and fixed airflow limitation, who presented with acromegaly. Head magnetic resonance imaging revealed a pituitary microadenoma and open lung biopsy revealed a multifocal proliferation of neuroendocrine cells which were immunopositive for both corticotropin and growth hormone-releasing hormone. To our knowledge, this is the first report of acromegaly associated with IDHPNC, and supports the possibility that IDHPNC may fall at one extreme of the spectrum of disorders encountered in multiple endocrine neoplasia type 1.