Visceral myopathy of the colon mimicking Hirschsprung's disease. Diagnosis by deep rectal biopsy.

A 51-year-old man presented with a history and physical findings consistent with adult Hirschsprung's disease. An inadvertent transmural rectal biopsy led to the unexpected diagnosis of a visceral myopathy, a diagnosis which was confirmed by subsequent colectomy. The pathological findings are reviewed, and the potential use of transmural rectal biopsy in the diagnosis of smooth muscle disorders of the colon is discussed.