Skin nontumor

Infectious disorders


Last author update: 1 March 2016
Last staff update: 16 November 2020

Copyright: 2003-2023,, Inc.

PubMed Search: Malakoplakia [title] skin

Abha Soni, D.O., M.P.H.
Andrzej Slominski, M.D., Ph.D.
Page views in 2022: 2,611
Page views in 2023 to date: 1,251
Cite this page: Soni A, Slominski A. Malakoplakia. website. Accessed June 2nd, 2023.
Definition / general
  • Greek derivation: Malako-soft and Plako-plaque
  • Chronic granulomatous inflammation
  • Most commonly occurs in the genitourinary tract
  • Rarely occurs in skin (< 100 cases reported, Arch Pathol Lab Med 2008;132:113)
  • Co-involvement of the gastrointestinal tract and other visceral organs also rarely occurs
  • Likely due to inadequate killing of bacteria by macrophages or monocytes that exhibit defective phagolysosomal activity (eMedicine - Malakoplakia)
  • Partially digested bacteria accumulate in monocytes or macrophages, leading to deposition of calcium and iron on residual bacterial glycolipid
  • Basophilic inclusion structure that contains calcium is called Michaelis-Gutmann body, and is considered pathognomonic
  • Patients typically suffer from immunosuppression (HIV, cancer, lymphoma, post-transplant) or autoimmune diseases (SLE, rheumatoid arthritis)
  • Most cases are associated with E.coli
Clinical features
  • Most often affects the urinary tract, but may affect GI tract, lymph nodes, brain, bone, adrenals and skin
  • May present with papules, plaques, polyps, ulcers and sinuses
  • Skin lesions are non progressive but persistent firm nodules up to 2 cm in diameter
  • Skin colored, yellow or pink
  • May contain a central dimple or draining sinus
  • Histologic diagnosis required
Case reports
  • Antibiotics that concentrate in macrophages (quinolones, trimethoprim-sulfamethoxazole) are associated with a high cure rate
  • Antibiotic therapy against E. coli with surgery is most effective
Clinical images

Images hosted on other servers:
Missing Image

Purple plaque

Missing Image

After treatment

Microscopic (histologic) description
  • Confluent sheets of histiocytes (von Hanseman cells) with eosinophilic granular cytoplasm and eccentric nuclei
  • Cells contain characteristic basophilic bodies containing calcium (von Kossa+)
  • Round, sometimes laminated structures are known as Michaelis - Gutmann bodies
  • The targetoid pattern is accentuated by staining with PAS
  • Also histiocytes, neutrophils, plasma cells, lymphocytes and granulation tissue
Microscopic (histologic) images

Images hosted on other servers:
Missing Image Missing Image

Michaelis-Gutmann body

Missing Image

Calcified structures

Missing Image

Periodic acid Schiff stain

Missing Image

PAS, Von Kossa, Prussian blue

Positive stains
Electron microscopy description
  • Histiocytes containing phagolysosomes with intact or partially digested bacteria
  • The granules within the macrophages, which stain with PAS, contain engorged lysosomes that contain bacteria debris
Back to top
Image 01 Image 02