splenule

A splenule, also known as an accessory spleen or supernumerary spleen, is a small, benign nodule of splenic tissue that is separate from the main spleen. These ectopic splenic tissues are typically congenital anomalies resulting from the incomplete fusion of the splenic buds during embryonic development. Splenules are most commonly found near the hilum of the main spleen but can also occur in other locations within the abdominal cavity, such as the tail of the pancreas or the gonadal regions.

Most splenules are asymptomatic and incidental findings during imaging studies or surgeries. They generally measure less than 2 centimeters in diameter and contain normal splenic tissue, including red pulp and white pulp components. Their presence is usually benign and does not require treatment unless they cause symptoms or are mistaken for pathological growths.

Detection of splenules is often achieved through imaging modalities such as ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI). Nuclear medicine scans using technetium-99m-labeled heat-damaged red blood cells are highly specific for identifying ectopic splenic tissue.

While splenules are usually of no clinical concern, their recognition is important in certain contexts, such as distinguishing them from metastatic deposits or lymphadenopathy. They can also become involved in hematological disorders affecting the spleen, though such cases are rare.

In summary, a splenule is a small, benign splenic tissue nodule resulting from embryonic development, typically asymptomatic, and often identified incidentally during imaging or surgical procedures.