foamy histiocytes

Definition: Histiocytes that are laden with lipid (predominantly cholesterol ), and that have differentiated from circulating monocytes.

Images

 foamy macrophages in lung

• examples : amiodarone exposure
  • https://twitter.com/smlungpathguy/status/715529010176999424

 In tumors

• giant cell tumor of tendinous sheath
• xanthograuloma
  • https://twitter.com/VishwasParekh/status/709002101586857985

 In BAL

• https://twitter.com/pembeoltulu/status/725733193773637632

 In blood

• GM1 gangliosidosis
  • https://twitter.com/feldstej/status/725869126728716288

 foamy histiocytes in MAI lymphadenitis

• https://twitter.com/ktmontone/status/849243543055085572

 portal foamy histiocytes in lysosomal acid lipase deficiency

• https://twitter.com/francesc_riu/status/847500260545048576

 xanthomatous histiocytes in verruciform xanthoma

• https://twitter.com/Rami_AlRohil/status/1128124213284487175

 in dermis : dermal foamy histiocytes

• https://twitter.com/Annpathol/status/1458152974455300098

Digital cases (Digital slides)

 HPC:380 : Foamy macrophages in pulmonary alveoles.
 JRC:336 : Niemann-Pick’s disease (Spleen).

Etiology (Exemples)

 xanthomatous tumors

• xanthelasma
  • Image: https://twitter.com/VishwasParekh/status/721415356980555776

 histiocytoses

• Langerhans cell histiocytosis
• non-Langerhans cell histiocytosis
  • juvenile xanthogranunloma
  • Erdheim-Chester disease

 inherited metabolic diseases

• lysosomal storage diseases
  • lysosomal acid lipase deficiency
    • Wolman disease

Localization

 medullary foamy histiocytes
 splenic foamy histiocytes
 dermal foamy histiocytes
 renal foamy histiocytes

• glomerular intracapillary foamy histiocytes
• renal tubulary foamy histiocytes

 medullary foamy histiocytes

 lungs: lipid-laden macrophages in pulmonary alveoles