SN2 SHORT NOTE 5M ★ High-yield

Describe the types of giant cells with examples.

Pathology · 2nd Professional — Para-Clinical

Definition and Formation

Giant cells are large multinucleate cells formed by the fusion of macrophages or of other cells, or occasionally by nuclear division without cytoplasmic division.

Types of Giant Cell

Giant cell	Arrangement of nuclei	Found in
Langhans	Horseshoe or ring at the periphery of the cell	Tuberculosis, sarcoidosis, and other immune granulomas
Foreign body	Scattered randomly throughout the cytoplasm	Around suture, talc, splinters and other inert material
TOUTON	A ring of nuclei with foamy lipid-laden cytoplasm outside it	Xanthoma, xanthelasma, fat necrosis, dermatofibroma
Aschoff	Owl-eye or caterpillar nuclei	Rheumatic fever — the Aschoff body
REED–sternberg	Bilobed "owl-eye" nucleus with a prominent eosinophilic nucleolus	Hodgkin lymphoma — a neoplastic cell, not a macrophage
Warthin–finkeldey	Many small nuclei in a grape-like cluster	Measles
Osteoclast	Numerous, central	Normal bone resorption; giant cell tumour; hyperparathyroidism
Tumour giant cell	Bizarre, hyperchromatic, pleomorphic	Anaplastic malignant tumours
Syncytial (viral)	Multiple, with inclusion bodies	Herpes, cytomegalovirus, respiratory syncytial virus

CLINICAL PEARL

The arrangement of the nuclei is the whole answer. Peripheral horseshoe means Langhans and an immune granuloma; scattered at random means a foreign body; a ring with foamy cytoplasm outside means Touton and lipid. That one observation identifies the process before anything else is known about the section.

Langhans Compared with Foreign Body Giant Cells

Feature	Langhans	Foreign body
Nuclei	Peripheral, horseshoe	Random, throughout
Stimulus	Immune — persistent antigen with a T cell response	Non-immune — indigestible material
Associated cells	Epithelioid cells and lymphocytes	Few lymphocytes
Inclusions	None	The foreign material is often visible within the cell
Example	Tuberculosis	Suture granuloma

Functional Significance

Fusion increases the digestive capacity for material too large for a single macrophage
Giant cells are relatively poor phagocytes and are largely secretory
Their presence indicates chronicity — they take days to weeks to form

Applied Aspects

A Langhans giant cell with caseation is effectively diagnostic of tuberculosis in the Indian setting, and mandates acid-fast staining and culture
Reed–Sternberg cells are required for the diagnosis of Hodgkin lymphoma, but similar cells occur in infectious mononucleosis, so the context matters
Giant cell arteritis shows giant cells in the wall of the temporal artery with fragmentation of the internal elastic lamina; urgent steroids prevent blindness
Giant cell (osteoclastoma) tumour of bone occurs at the epiphysis of long bones after epiphyseal fusion, and gives a "soap-bubble" appearance radiologically
Foreign body giant cells around suture material are a common incidental finding in re-operation specimens and are of no consequence

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