[Lumbar panniculitis with subcutaneous abscess revealing pyonephrosis].Ann Dermatol Venereol. 2009 Oct; 136(10):727-9.AD
A clinical picture of hypodermitis in the lumbar region may reveal an abscess arising from infection due to pyonephrosis. We report a case below.
A 58 year-old woman consulted for an area of inflammation in the left lumbar region that had been present for two months. The area of inflammation appeared two days after physiotherapy sessions prescribed for lower back pain. Laboratory examinations revealed inflammation associated with moderate renal failure. A skin biopsy sample taken from around the inflamed area showed septal hypodermitis. Ultrasound examination revealed a pocket of liquid measuring 7 x 2 x 2 cm; Proteus mirabilis was isolated following ultrasound-guided needle aspiration,. Magnetic resonance imaging (MRI) and uroscan revealed pyonephrosis with suffusion into the hypodermis and left lumbar fossa.
This was a case of bacterial hypodermitis with abscesses secondary to pyonephrosis. Pyonephrosis may be transferred to the skin, causing fistulas and subcutaneous pus collection. In such rare and potentially misleading clinical settings, the diagnosis can be established by imaging.