Cluster of grapes sign | Radiology Signs

Answer:

The cluster of grapes sign represents the appearance of multiple small, rounded, fluid-containing spaces within a pathological mass or collection. This sign is encountered in several distinct clinical contexts with different underlying etiologies. In synovial sarcoma, a malignant soft tissue tumor, the cystic spaces result from hemorrhage, necrosis, or myxoid degeneration within the tumor mass. In pyogenic liver abscesses, the sign represents the coalescence of multiple small abscesses into a single large multiloculated cavity. In hydatid disease affecting the liver or spleen, daughter cysts develop within a parent echinococcal cyst, creating a similar appearance. The sign may also be observed in other cystic lesions demonstrating internal compartmentalization.

Why is it called so?

The sign is named for its visual resemblance to a cluster or bunch of grapes, where the multiple small rounded cystic spaces recall the appearance of individual grapes grouped together on a vine. This descriptive terminology aids in rapid visual recognition and communication of the radiological finding across imaging modalities such as ultrasound, CT, and MRI.

Pathophysiology

In synovial sarcoma, the cystic spaces develop as a consequence of tumor degeneration, with hemorrhagic products and necrotic material creating fluid-filled cavities within the solid tumor component. In pyogenic abscesses, coalescence occurs as neighboring small abscesses merge into a single larger multiloculated structure. In hydatid disease, the pathophysiology involves parasitic colonization with subsequent development of multiple daughter cysts within the primary echinococcal cyst through internal budding and proliferation. The visualization of these fluid-containing spaces on imaging reflects the underlying pathological process specific to each condition.

Alternative names: Bowl of grapes sign (particularly in synovial sarcoma context)