Erythema nodosum as first clinical manifestation of metastatic neuroendocrine tumor: A case report.

Erythema nodosum (EN) is a reactive inflammatory panniculitis, which has been associated with medications, infections, autoimmune and autoinflammatory diseases. It has rarely been associated with neoplasms. We present the case of a 61-year old woman who was admitted because 3-week history of painful erythematous subcutaneous nodules on the lower limbs clinically consistent with EN, which was confirmed by skin biopsy. The patient denied use of medication. No general or systemic symptoms were present. As part of his study, an abdominal ultrasound and later magnetic resonance imaging (MRI) was done and lesions suggestive of liver metastases were reported. An ultrasound guided liver biopsy was then performed and pathology studies evidence a well differentiated grade II gastro-enteropancreatic neuroendocrine tumor (GEP-NET). A 9mTc-Octreotide scintigraphy evidenced a positive expression of somatostatin receptor in the liver and in a nodular mesenteric lesion in contact with an intestinal loop. The patient began treatment with lanreotide and was scheduled for cytoreductive surgery. During surgery, 50 cm of the small intestine, gallbladder, mesenteric fat and a 4.2x3.3 × 1 cm tumor located on the VII hepatic lobe were resected. Subsequently EN lesions of the lower extremities resolved. We present a rare case of GEP-NET-associated EN, that improved with surgical tumor cytoreduction and hormone therapy.