The workup of pleural-based nodules often requires a biopsy to exclude malignancy. Thoracic splenosis, a rare entity that can occur in patients who have had simultaneous splenic and diaphragmatic trauma, can occasionally present as left-sided pleural-based nodules. We describe a case in which slowly enlarging pleural nodules were diagnosed noninvasively as thoracic splenosis by radionuclide imaging without the need for a biopsy.
A 58-year-old male Vietnam veteran was referred for incidental findings on chest radiograph of 2 large pleural nodules in the left hemithorax. The patient remained asymptomatic. His past medical history included medication-controlled hypertension, sickle cell trait, alcoholism and diverticulosis. He smoked 1 pack-per-day for 42 years and worked a variety of custodial jobs; he was unaware of specific exposure to asbestos. Of note, 40 years ago the patient sustained extensive combat wounds and relates multiple surgeries to his left chest, stomach, intestines, and left arm. He vaguely recalls having a prolonged ventilator wean, tracheostomy, gastrostomy, and a left thoracostomy tube. Eventually he had a full recovery. Upon evaluation by our service, a full review of systems was unremarkable. Exam was notable only for multiple healed incisions in the mid-abdomen and left chest wall. Chest X-ray and CT scans showed 2 large left pleural-based nodules, the largest of which was 6 cm x 2.9cm. The nodules were homogeneous in appearance and not calcified. When compared to a CT scan performed 10 years prior (performed at the time for diverticular bleeding) the nodules had nearly doubled in size. To confirm our initial impression of thoracic splenosis, a liver-spleen sulfur-colloid scan was performed. This demonstrated 2 small foci of enhancement that correlated anatomically with the nodules on the CT scan. The diagnosis of thoracic splenosis was thereby confirmed by radionuclide imaging without the need for a biopsy.
First described in 1937 by Shaw and Shafi , thoracic splenosis is a rare condition that usually follows simultaneous splenic and diaphragmatic injury, with autotransplantation of splenic tissue into the left hemithorax . The resulting nodules are usually incidental findings from chest imaging, but because they can radiographically mimic malignancy, biopsy is often needed. Biopsy in this setting is often nondiagnositic, may have complications, or may result in resection of functional splenic tissue with an associated theoretical increased incidence of infection . Therefore in the appropriate clinical setting, a noninvasive means of diagnosis is preferred. Radionuclide imaging was first reported in 1971 to diagnose abdominal splenosis, and recently has been used in scattered reports for thoracic splenosis . As the nodules in our patients slowly enlarged over the years, it slightly raised the possibility of the nodules being malignant in nature. With nodule enhancement on the liver-spleen scan, however, the patient and our staff were reassured that the nodules are indeed splenic tissue, which is benign in nature.
The finding of multiple pleural-based nodules in a patient with a history of splenic and diaphragmatic trauma should raise the possibility of thoracic splenosis. Diagnosis of this rare entity can be confirmed by noninvasive radionucleotide imaging.
Jaspal Singh, None.