['Mast cell counts have been advocated as useful in the pathological diagnosis of interstitial cystitis. To determine the clinical significance of mucosal and detrusor muscle mast cells we quantified mast cells within the lamina propria and detrusor muscle in nonulcerative interstitial cystitis, and various inflammatory and neoplastic bladder diseases.', 'Mast cells from Giemsa stained sections were enumerated from 8 cases of clinically diagnosed nonulcerated interstitial cystitis and 32 control cases having inflammatory or neoplastic bladder disease. Cystectomy specimens from controls also included sections from normal (5) and inflamed transitional mucosa (4) distant from the invasive tumor.', 'There was no significant difference in mast cell counts when considered absolutely or relative to the muscle-to-mucosa ratio in cases of nonulcerative interstitial cystitis and controls.'] Are mast cell counts useful in the diagnosis of nonulcerative interstitial cystitis?