[Table/Fig-9]:
Differential diagnosis of sarcomas of thyroid gland.
| LMS | MFH | AC-T | MCT (Spindle cell variant) | METASTASIC MFH /LMS |
|
|---|---|---|---|---|---|
| Incidence | 0.014% | RARE | ~5% | RARE | RARE |
| Origin | Smooth muscles of capsular blood vessels | Uncertain origin Probably fascia surrounding thyroid |
Undifferentiated | Para follicular C-cells |
? multipotent fibroblast |
| Age/sex | >55, F>M | >65, F>M | >60, F>M | 40-60, F>M | >50, F>M |
| Morphology | Pleomorphic spindle cells in sheets & whorls, necrosis & mitosis | Plump spindle cells in storiform pattern, Tumor giant cells |
Varied | Spindle out cells | Varied |
| IHC | SMA+, Vimentin + | CD 68+, Vimentin+ | CK+ TG – SMA-, CD 68- |
Calcitonin + TG- |
Vimentin+ CD68/ SMA+ TG- |
| Prognosis | Poor | Poor | Dismal | Better | Poor |
LMS: Leiomyosarcoma, MFH: Malignant Fibrous Histiocytoma, AC-T: Anaplastic Carcinoma Thyroid (TG- Thyroglobulin, TTF- Thyroid transcription factor, Ck- cytokeratin, SMA = Smooth muscle actin, IHC: Immunohistochemistry.