Malignant histiocytosis. Ultrastructural and immunocytochemical characterization

Area of Science:

• Oncology
• Cell Biology
• Pathology

Background:

• Malignant histiocytosis is a rare neoplastic proliferation of histiocytes.
• Accurate diagnosis relies on distinguishing neoplastic histiocytes from other cell types.

Purpose of the Study:

• To characterize the immunohistochemical and ultrastructural features of neoplastic cells in malignant histiocytosis.
• To evaluate the utility of intracytoplasmic muramidase (CM) as a diagnostic marker.

Main Methods:

• Immunohistochemistry and transmission electron microscopy were used to examine lymph node biopsies from four patients.
• Immunocytochemical detection of intracytoplasmic muramidase (CM) was performed.

Main Results:

• Neoplastic cells exhibited irregular surface projections, lobulated nuclei, and abundant cytoplasm with lysosomes and mitochondria.
• Phagocytosis was evident, and Langerhans' granules were absent.
• Intracytoplasmic muramidase (CM) was strongly positive in neoplastic histiocytes, confirming myeloid or histiocytic origin.

Conclusions:

• Ultrastructural morphology and the presence of intracytoplasmic muramidase (CM) are valuable for diagnosing malignant histiocytosis.
• These findings help exclude epithelial origins and confirm neoplastic macrophage characteristics.