Small bowel (small intestine)
Benign tumors and tumor-like conditions
Clofazimine toxicity

Topic Completed: 1 August 2012

Revised: 13 March 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Clofazimine small bowel

Hanni Gulwani, M.B.B.S.
Page views in 2019: 134
Page views in 2020 to date: 14
Cite this page: Gulwani H. Clofazimine toxicity. website. Accessed February 27th, 2020.
Definition / general
  • Clofazimine is drug for leprosy, Mycobacterium avium complex in HIV patients, graft versus host disease
  • Poorly soluble but orally bioavailable small molecule drug that massively accumulates in macrophages when administered over prolonged periods of time (PLoS One 2012;7:e47494)
  • May cause severe abdominal pain, red skin discoloration and ichthyosis
Case reports
Microscopic (histologic) description
  • Red crystals in frozen section with bright red birefringence but clear in routinely processed histologic sections
  • Causes histiocytosis resembling lymphoma, plasmacytosis (Am J Surg Pathol 2000;24:129)
Microscopic (histologic) images

Images hosted on other servers:

Crystal storing histiocytosis: numerous large epithelioid eosinophilic cells intermingle with a mild plasmacytic infiltrate within a fibrous stroma; at high power, cells contain numerous needle-like crystals; D: birefringence under polarized light microscopy

Mononuclear epithelioid cells are strongly CD68+ (KP1) and CD68+ (PGM1), supporting a histiocytic lineage; plasma cells are CD138+; note the weak cytoplasmic positivity in histiocytes and stronger cytoplasmic positivity in plasma cells for IgG, κ light chain and λ light chain

Electron microscopy description
  • Clear spaces with some osmiophilic bodies
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