E3355. Lumps and Bumps in the Abdominal Wall: When Should You be Concerned?
  1. Seng Thipphavong; Princess Margaret Cancer Centre
A wide spectrum of pathologies can occur in the anterior abdominal wall soft tissues, ranging from nonneoplastic to malignant processes. Often, the patient will complain of a palpable mass and an imaging investigation is initiated for a ventral hernia. What happens when a solid-appearing mass is found in the abdominal wall? We will discuss a variety of solid-appearing masses or masslike processes involving the abdominal wall, with a focus on when imaging is diagnostic for a benign process or when biopsy tissue sampling is necessary.

Educational Goals / Teaching Points
Masslike processes involving the abdominal with imaging characteristics that are definite for a benign entity not requiring biopsy include hematoma, abscess, and endometriosis. Fat-containing masses in the abdominal wall include fat necrosis, lipoma, and liposarcoma. Benign neoplasms occurring in the abdominal wall that may require tissue biopsy for diagnosis include hibernoma, nerve sheath tumor, or leiomyoma. Malignant masses in the abdominal wall often requiring tissue biopsy include dedifferentiated liposarcoma, lymphoma, and solitary fibrous tumor.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
A spectrum of disease processes involving the soft tissues of the abdominal wall will be discussed, including the following nonneoplastic processes (hematoma, abscess, endometriosis, gossypiboma, fat necrosis, Rosai-Dorfman disease), benign neoplastic masses (hemangioma, hibernoma, lipoma, nerve sheath tumor, leiomyoma), and malignant masses (lymphoma, solitary fibrous tumor, dermatofibrosarcoma protuberans, liposarcoma, mesothelioma, metastases).

Lumps and bumps in the abdominal wall often warrant imaging for further investigation. The radiologist can make the important differentiation between benign 'no-touch' lesions and directing patients for tissue biopsy for indeterminant or aggressive appearing masses.