title: Extragenitourinary malakoplakia in a patient with myeloma clinically mimicking extramedullary myelomatous disease.
abstract: Malakoplakia is a rare granulomatous disorder of unknown etiology and usually affects patients with underlying immunosuppression. This disorder usually involves the genitourinary tract but has been reported in a wide array of anatomical sites. We present a case of extragenitourinary malakoplakia, developing in a patient with a history of plasma cell myeloma, which clinically mimicked recurrent extramedullary myelomatous involvement. Radiologically, this lesion was a 10-cm soft-tissue mass located in the left flank and iliacus muscle. Excisional biopsy revealed a histiocytic infiltrate with histologic features diagnostic of malakoplakia. This case demonstrates the clinical and pathologic diagnostic challenges of malakoplakia arising outside the genitourinary tract. Given that it can closely mimic malignancy in such settings, malakoplakia should be considered in the differential diagnosis of soft-tissue masses developing in patients with hematologic malignancy and iatrogenic immunosuppression. This case highlights the importance for awareness on the part of clinicians, radiologists, and pathologists that malakoplakia can present as a soft-tissue mass.
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
authors.forename: Siraj M
authors.initials: SM
authors.lastname: El Jamal
authors.forename: Sharp F
authors.initials: SF
authors.lastname: Malak
authors.forename: R Michelle
authors.initials: RM
authors.lastname: Cox
authors.forename: Robert B
authors.initials: RB
authors.lastname: Lorsbach
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000077723:Cefepime; D002511:Cephalosporins / Q000627:therapeutic use; D004927:Escherichia coli Infections / Q000150:complications / Q000188:drug therapy; D006801:Humans; D008287:Malacoplakia / Q000150:complications* / Q000382:microbiology / Q000473:pathology*; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use; D009101:Multiple Myeloma / Q000150:complications* / Q000628:therapy; D009362:Neoplasm Metastasis / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000473:pathology; D033581:Stem Cell Transplantation
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D008795:Metronidazole; D000077723:Cefepime