Lysozyme by IHC

Alphabetical Test listing

Lysozyme by IHC-12376 - Technical only, 12379 - Technical & interpretation

Lysozyme by IHC
12376 - Technical only, 12379 - Technical & interpretation
  • All IHC stains will include a positive control tissue
  • The bacteriolytic enzyme acts on walls of susceptible micro-organisms by cleavage of the bond between N acetyl muramic acid and N acetylglucosamine
  • Useful in the workup of myeloid leukemias. Variable staining pattern seen in normal and leukemic myeloblasts and monoblasts (range from positive to negative in various studies)1,2,4,6
  • Lymphoid cells and their malignancies are negative for lysozyme
  • Natural killer cells, red blood cells, erythroblasts and megakaryocytes are also negative1
  • Majority of epithelioid histiocytes associated with toxoplasmic lymphadenitis and granulomatous diseases show moderate to strong positivity for intracellular lysozyme 1
  • Lysozyme is a well known marker of benign reactive macrophages in tissue sections, but appears not to be a reliable marker of malignant histiocytes 2
  • A large number (26 of 29 and 2 of 2) of extramedullary myeloid cell tumors (granulocytic sarcomas) show strong cytoplasmic staining with lysozyme (helpful in diagnosing cases which lack histologic evidence of granulocytic differentiation and may be negative with CAE)3-5
  • Focal positivity for lysozyme seen in some cases of granular cell tumor

Submit a formalin-fixed, paraffin embedded tissue block


Formalin-fixed, paraffin embedded (FFPE) tissue block


FFPE tissue section mounted on a charged, unstained slide


Ambient (preferred)

  • Unlabeled/mislabeled block
  • Insufficient tissue
  • Slides broken beyond repair
AHL - Immunohistochemistry
Mo - Fr
1 - 2 days

Immunohistochemical staining and microscopic examination


If requested, an interpretive report will be provided



  • Lysozyme (Muramidase) is an intracellular enzyme found in myeloid cells, monocytes and their precursors, histiocytes and some body fluids and secretions
  • Lysozyme is present in a variety of normal human tissues

Staining pattern

  • Diffuse granular cytoplasmic


  1. AJP 89:351-366, 1977.
  2. AJH 21:99-109, 1986.
  3. Archives of Pathol and Lab Medicine 120:62-67, 1996.
  4. Cancer 71:124-32, 1993.
  5. AJCP 102:55-60, 1994.
  6. AJCP 67:481-484, 1977.
88342 - 1st stain
88341 - each additional stain