Mediastinum
Thymic carcinoma
Sarcomatoid
Author: Hanni Gulwani, M.B.B.S.
Topic Completed: 1 December 2012
Minor changes: 10 June 2020
Copyright: 2003-2020, PathologyOutlines.com, Inc.
PubMed Search: Sarcomatoid thymic carcinoma
Table of Contents
Definition / general | Terminology | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Differential diagnosisCite this page: Gulwani H. Sarcomatoid. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mediastinumsarcomatoid.html. Accessed August 12th, 2020.
Definition / general
- Very rare; usually presents as rapidly growing, anterior mediastinal mass
- Must exclude metastases before making this diagnosis
- May arise from malignant transformation of preexisting spindle cell thymoma (Am J Surg Pathol 1999;23:691)
- Aggressive - recurrence, metastasis and death are common
Terminology
- Also called spindle cell thymic carcinoma
Case reports
- 43 year old man with tumor arising in metaplastic thymoma (Histopathology 2008;52:409)
- 63 year old woman with tumor arising in metaplastic thymoma (Int J Surg Pathol 2011;19:677)
Gross description
- Large (mean 15 cm), well circumscribed, locally infiltrative
- Firm cut surface, focal hemorrhage, necrosis, cystic changes
Microscopic (histologic) description
- Irregular fascicles of fusiform and pleomorphic cells with amphophilic or eosinophilic cytoplasm, hyperchromatic nuclei, prominent nucleoli (at least focally), brisk mitotic activity, often atypical mitotic figures
- May have epithelioid foci
- Usually transitional areas with spindle cell thymoma
- May also have lymphoepithelioma-like or anaplastic areas
- Rarely rhabdomyogenic foci with cross striations
Microscopic (histologic) images
Images hosted on other servers:
Atypical population
of spindle cells
with frequent
mitotic figures
Positive stains
Electron microscopy description
- Focal junctional complexes between spindle cells, tonofibrils
Differential diagnosis
- Germ cell tumor
- Malignant schwannoma: triton tumor
