The toluidine blue test: an aid in the diagnosis and treatment of early squamous cell carcinomas of mucous membranes.

Early diagnosis of squamous cell carcinoma on mucosal surfaces can be lifesaving, and examination of mucosal sites should be included in the general dermatologic examination. Difficulty in distinguishing the erythematous lesions appropriate for biopsy and treatment can be partially overcome with the use of a supravital stain well known to oral surgeons. This paper recommends the addition of this test to the dermatologist's armamentarium. Five patients with mucosal in situ squamous cell carcinoma were treated. Three had squamous cell carcinoma of the glans penis, one of the vulva, and one of the oral mucosa. In all patients the toluidine blue test was helpful in the diagnosis of subclinical malignant epithelium, in the delineation of the lesion borders as a guide for surgery, and, postoperatively, in the detection of early disease recurrence. The toluidine blue test, which is a simple procedure accessible to all dermatologists, can help achieve early diagnosis and effective treatment of mucosal squamous cell carcinoma.