Primary splenic melanoma associated with small intestinal serosal implants causing intussusception - a case report

Introduction: Melanoma is a highly aggressive tumor that carries a poor prognosis. There are several reported cases of secondary splenic melanoma but there is only one reported case of primary splenic melanoma yet. Case presentation: A 35-year-old male, complaining from left lumbar pain. Abdominal ultrasound revealed a mass at the lower pole of the spleen measuring 10x7x7 cm. Computed Tomography (CT) described a necrotic focal lesion involving its lower pole measuring 11 x 9 cm. US-guided fine needle aspiration (FNA) was suggestive of lymphoma, but tissue biopsy was recommended. So, the patient underwent open diagnostic splenectomy which revealed the diagnosis of malignant melanoma. Only two weeks after being discharged from the hospital, he was re-admitted by acute intestinal obstruction for which he underwent exploration which revealed an ileo-ileal intussusception near the ileocecal junction with multiple pigmented malignant nodules on the wall of the small intestine. Resection of the involved small intestinal part including intussusception was done. Pathological examination revealed malignant melanoma infiltrating the whole intestinal wall thickness from outside (confirming its metastatic nature) and infiltration of the mesenteric LN by the same tumor tissue. The patient died 6 months later after being diagnosed with brain metastasis. Conclusion: Primary splenic melanoma is extremely rare with only one reported case in literature. This report is not only unique because of the rarity of the primary splenic melanoma but the intussusception caused by melanomatous serosal deposits is extremely rare as well.