Spontaneous regression of intestinal malignant melanoma from an occult primary site.

A 55-year-old male patient who had melena and intussusception that proved to be due to malignant melanoma of the small intestine is described. History and close examination failed to show any evidence of a primary lesion. The diagnosis was made after a biopsy was performed on two lesions in the neck. This was followed by a palliative and incomplete resection of an involved ileal segment. The patient did not receive chemotherapy, radiotherapy, or immunotherapy. He is now alive 8 years after diagnosis without evidence of malignancy. This case represents spontaneous regression of malignant melanoma of the small intestine that is considered either a primary intestinal tumor or a metastatic tumor from an occult regressed primary. The latter assumption makes this case unique in that spontaneous regression occurred twice, once in the occult primary lesion and once in the intestinal metastases.