Eric J. Heffernan

Recurrent Pyogenic Cholangitis: From Imaging to Intervention

OBJECTIVE The objective of this article is to familiarize the reader with the sonographic, CT, MR cholangiopancreatography, and ERCP appearances of recurrent pyogenic cholangitis and to briefly review the role of interventional radiology in the management of this disease. CONCLUSION Recurrent pyogenic cholangitis is a complex disease, the incidence of which is increasing in Western countries. Radiologists should be aware of the role of imaging in the diagnosis of this disease and the use of imaging as a guideline for subsequent intervention.

Ossifying lipoma of the thigh.

Lipomas are common soft-tissue tumours that are usually found in the subcutaneous adipose tissue. Occasionally, they may contain mesenchymal elements other than adipose tissue, including osseous components. These ossifying lipomas are usually located near or within bone, and it is very rare for a lipoma with no connection to bone to contain mature osseous tissue. We describe a case of a symptomatic ossifying intramuscular lipoma of the thigh.

Primary retroperitoneal masses: what is the differential diagnosis?

Primary retroperitoneal masses include a diverse, and often rare, group of neoplastic and non-neoplastic entities that arise within the retroperitoneum but do not originate from any retroperitoneal organ. Their overlapping appearances on cross-sectional imaging may pose a diagnostic challenge to the radiologist; familiarity with characteristic imaging features, together with relevant clinical information, helps to narrow the differential diagnosis. In this article, a systematic approach to identifying and classifying primary retroperitoneal masses is described. The normal anatomy of the retroperitoneum is reviewed with an emphasis on fascial planes, retroperitoneal compartments, and their contents using cross-sectional imaging. Specific radiologic signs to accurately identify an intra-abdominal mass as primary retroperitoneal are presented, first by confirming the location as retroperitoneal and secondly by excluding an organ of origin. A differential diagnosis based on a predominantly solid or cystic appearance, including neoplastic and non-neoplastic entities, is elaborated. Finally, key diagnostic clues based on characteristic imaging findings are described, which help to narrow the differential diagnosis. This article provides a comprehensive overview of the cross-sectional imaging features of primary retroperitoneal masses, including normal retroperitoneal anatomy, radiologic signs of retroperitoneal masses and the differential diagnosis of solid and cystic, neoplastic and non-neoplastic retroperitoneal masses, with a view to assist the radiologist in narrowing the differential diagnosis.

Aggressive angiomyxoma of the thigh.

Aggressive angiomyxoma is a rare tumour that typically occurs in the perineum in women of reproductive age. A small number of cases occurring in men have been reported, all of which were located in the low pelvis, perineum or scrotum. While benign, the tumour is locally infiltrative and consequently has a high rate of local recurrence following surgery; therefore, accurate pre-operative diagnosis is important. The characteristic location of these tumours in the low pelvis or perineum has led to speculation that aggressive angiomyxomas arise from a mesenchymal cell that is unique to the perineum. We describe a case of aggressive angiomyxoma arising in the thigh of a 54-year-old man, which we believe is the first reported instance of this rare neoplasm occurring remote from the pelvis or perineum in a male patient. Cross-sectional imaging demonstrated a well-defined mass that had low density on CT and high intensity on fluid-sensitive MR sequences. Biopsy was non-diagnostic and excision was performed. At histological analysis, the tumour exhibited the characteristic features of aggressive angiomyxoma, with bland spindle cells and large, hyalinised blood vessels in a hypocellular myxoid matrix. Extensive immunohistochemical staining further supported the diagnosis. While the imaging features of these tumours are non-specific and suggestive of myxoid neoplasms, the diagnosis should be considered whenever biopsy of a myxoid-appearing mass yields hypocellular, non-diagnostic material, despite adequate sampling.

The Radiology of Antibiotic-Impregnated Cement

OBJECTIVE The purpose of this article is to illustrate the radiologic appearances of the various forms of antibiotic-impregnated cement. CONCLUSION Although the radiologic appearances of antibiotic-impregnated polymethyl methacrylate (PMMA) and regular PMMA are identical, peculiarities in the position and morphology of antibiotic-impregnated cement, as illustrated in this review, usually enable the radiologist to differentiate between the two. Its presence indicates one of two things: Either infection was present at the time the PMMA cement was inserted, or there was a high potential for the development of local sepsis, such as in cases of an open fracture. On the basis of this finding, the radiologist should carefully search for evidence of osteomyelitis.