Case 237 -- Flank Mass

Contributed by Richard E. Whisnant, MD, N. Paul Ohori, MD and William Pasculle, ScD
Published on line in June 2000


RL is a 30 year old male plumber who presented in April, 2000 for evaluation of an enlarging and painful right flank mass. The patient's past medical history included the removal of a subcutaneous mass removed from this area five months prior to admission. The resected surgical specimen surgical specimen was diagnosed as a fibrolipoma and fragments of skeletal tissue, with acute inflammation. He was apparently treated post-operatively with antibiotics, and there was no difficulty with wound healing. Over the following months, he developed increasing pain and ill-defined mass in this area, with no overlying skin changes. He also had intermittent fever and malaise. Computerized tomography evaluation of this area was performed during the present admission, which showed a right lung base infiltrate with associated pleural thickening, contiguous with enlarged and infiltrated right psoas, erector spinae, and quadratus lumborum muscles. Subsequently, the patient was referred for CT-guided fine needle aspiration of both the lung and right flank (CT Images 1 and 2). This specimen was sent for cytology and culture.


The cytology specimen showed predominantly neutrophils and necrotic debris (Image 3). Also present were sulfur granules composed of filamentous rods (Images 4, 5, and 6), consistent with Actinomyces sp.


The cultures from this specimen several days later grew a small number of molar-tooth colonies, positively identified as Actinomyces israelii (Image 7). This culture also subsequently grew light Haemophilus (Actinobacillus) actinomycetem comitans.


The slides from the original surgery in November were subsequently reviewed. On re-examination, the specimen was diagnosed as acute and chronic panniculitis, characterized by a mixed septal and lobular pattern with abundant neutrophils (Images 8 and 9).


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