Author: Nat Pernick, M.D. (see Authors page)

Revised: 20 November 2015, last major update June 2012

Copyright: (c) 2003-2015,, Inc.

PubMed Search: lysozyme[title]
Definition / General
  • Also called muramidase
  • Histiocytic enzyme that cuts muramic acid linkages in walls of bacterial cells (Wikipedia)
Micro Images

Images hosted on Pathout server:

Orbit: myeloid sarcoma

Thyroid gland: histiocytes stain strongly in palpation thyroiditis

Images hosted on other servers:

Acute myelomonocytic leukemia (M4)

Vagina: myeloid sarcoma

Images hosted on
Missing Image

Soft tissue: hemosiderotic fibrohistiocytic lipomatous lesion

Positive Staining - Normal
  • Nonspecific stain for histiocytes (granulomas), monocytes, neutrophils
  • May also stain some epithelial cells (pleomorphic adenoma)
  • Goblet cells and related lesions (goblet cell carcinoid)
  • Breast lactating lobules
Positive Staining - Disease
  • Acinic cell carcinoma (breast, salivary gland, Am J Surg Pathol 2009;33:1137)
  • Acute myelomonocytic leukemia (M4), acute monocytic leukemia (M5)
  • Adenocarcinoma (various sites)
  • Ampulla: Paneth cell carcinoma
  • CNS: chordoma
  • Eye: oncocytoma of conjunctiva
  • Histiocytic lesions: histiocytoma, histiocytic sarcoma, Rosai Dorfman disease
  • Langerhans cell histiocytosis
  • Mastocytosis
  • Myeloid sarcoma
  • Renal collecting duct / Bellini duct carcinoma
  • Salivary gland intercalated duct lesions (Am J Surg Pathol 2009;33:1322)
  • Skin: granuloma annulare, multicentric reticulohistiocytosis, synovial metaplasia, xanthogranuloma
  • Spleen: angiosarcoma and hemangioma (often, Mod Pathol 2000;13:978), littoral cell angioma
Negative Staining
  • Breast: histiocytoid variant of lobular carcinoma
  • Dendritic cells
  • Inflammatory pseudotumor
  • Interdigitating dendritic cell sarcoma
  • Skin: necrobiosis lipoidica