Thoracic splenosis: a great mimic diagnosed by functional imaging

Area of Science:

• Nuclear Medicine
• Radiology
• Surgical Pathology

Background:

• Splenosis involves ectopic splenic tissue, often after splenic rupture, commonly in the abdomen but also in rarer sites like the thorax.
• Thoracic splenosis presents a diagnostic challenge, mimicking malignancy on imaging and often being asymptomatic.
• Accurate diagnosis is crucial to prevent unnecessary invasive procedures for suspected neoplasms or metastatic disease.

Purpose of the Study:

• To highlight the diagnostic utility of nuclear medicine techniques in identifying splenosis, particularly in thoracic locations.
• To present two cases where functional imaging confirmed splenosis, differentiating it from malignant conditions.
• To emphasize the importance of considering splenosis in the differential diagnosis for patients with a history of splenic trauma.

Main Methods:

• Case presentation of two patients with suspected thoracic and abdominal lesions.
• Utilized Positron Emission Tomography/Computed Tomography (PET/CT) for initial metabolic characterization.
• Employed 99mTc-Heat-Damaged Red Blood Cells (99mTc-HDRBC) scintigraphy for definitive diagnosis of splenosis.

Main Results:

• In the first case, PET/CT and 99mTc-HDRBC scintigraphy confirmed benign pleural and abdominal splenosis in a patient with a history of trauma.
• In the second case, 18F-PSMA PET/CT suggested malignancy, but 99mTc-HDRBC scintigraphy definitively diagnosed multi-compartmental splenosis.
• Functional imaging successfully differentiated splenosis from neoplastic or metastatic lesions, avoiding further invasive workup.

Conclusions:

• Nuclear medicine, especially 99mTc-HDRBC scintigraphy, is invaluable for diagnosing splenosis.
• Considering splenosis in patients with a history of splenic trauma is essential for accurate diagnosis.
• Functional imaging aids in distinguishing splenosis from malignant entities, optimizing patient management.