Objectives

Discuss the importance of extraosseous, non-skeletal multiple myeloma in the abdomen and
pelvis, an often unrecognized finding though one of clinical significance.

Review the key imaging findings of extraosseous multiple myeloma in both computed
tomography and magnetic resonance with respect to lesion distribution, nodularity,
infiltration, enhancement, associated ancillary features, and other useful signs for suggesting
the diagnosis.

Background

Multiple myeloma (MM) accounts for 1% of all malignancies. Extraosseous involvement has been considered rare, but in fact is seen in approximately 10-16% of patients with MM. It is more common in younger patients, in those with aggressive subtypes of myeloma, and in
cases with a history of autologous or allogenic stem cell transplantation. Imaging plays a role in promoting accurate and early detection both for workup and follow-up

Imaging findings OR Procedure findings

Extraosseous myeloma can affect almost any organ system; however, the lymph nodes, pleura, and liver are most commonly involved. There are no specific imaging findings of extraosseous myeloma, which often mimics other disorders. Common imaging findings include homogeneously dense soft-tissue masses without necrosis or calcification on CT and low signal on T2-weighted MRI sequences

Conclusion

Given the poor prognosis that extraosseous disease of MM confers, multimodality imaging plays an important role in the early detection of this disease in myeloma patients.

There are no specific findings of extraosseous myeloma. Soft-tissue masses in a patient with myeloma should be considered suspicious for extraosseous myeloma

Objectives

Discuss peritoneal carcinomatosis (PC), its most frequent etiologies and routes of spread.
Propose a diagnostic algorithm for patients with unknown primary presenting with the
isolated imaging finding of peritoneal carcinomatosis.
Recognize key image findings and clinical clues that make peritoneal carcinomatosis less
likely in order to propose a useful differential diagnosis.

Background

PC is the most common malignant process in the peritoneal cavity. Carcinomas from the gastrointestinal tract, ovary, breast, lung, and uterus may metastasizeto the peritoneal surface. PC has historically been considered to be the terminal stage of malignant diseases;
however, since the 1990’s, patients without extraperitoneal metastases treated with combined cytoreductive surgery and chemotherapy have demonstrated improved loco-regional control of disease. The role of the radiologist includes diagnosing PC at an early stage, identifying patients likely to benefit from aggressive therapies and excluding carcinomatosis mimics.

Besides PC, a wide variety of diseases can involve the peritoneum. Differential diagnoses can be narrowed if imaging findings are correlated with clinical information.

Imaging findings OR Procedure findings

Ascites, thickened and enhancing peritoneal lining, omental and mesenteric involvement and adhesions compromising bowel loops are characteristic findings in PC. There are also hot spots to be assessed where seeding often occurs.

Common imaging mimics must be considered. Minors simulators are self-limited entities and include fat necrosis, omental infarction and epiploic appendagitis. Major mimics include tuberculous peritonitis, sclerosing encapsulating peritonitis, mesothelioma, pseudomyxoma
peritonei and lymphomatosis.

Conclusion

There are no pathognomonic imaging findings of PC. Early and accurate diagnosis can improve management of patients.
Differentials must include both neoplastic and infectious/inflammatory entities.