Inflammatory monomorphic undifferentiated sarcoma with distinct clinical and pathological features: a 'new' entity?
OBJECTIVE
To describe two patients with a highly aggressive, apparently 'new' and rare soft tissue and bone malignancy of childhood and early adult life that we have named inflammatory monomorphic undifferentiated sarcoma.


RESULTS
Two histologically identical tumours located in the proximal humerus and the anterior chest wall of males aged 6 and 31 presented as solitary, painful, tender, necrotising, masses, associated with fever, leukocytosis and negative microbiological cultures. The extensively necrotic resected tumours consisted of large, monomorphic epithelioid cells with vesicular nuclei, prominent eosinophilic nucleoli, and abundant eosinophilic cytoplasm surrounded by numerous neutrophils and eosinophils which formed sterile microabscesses. Immunohistochemical and ultrastructural studies revealed no specific differentiation. Both tumours were very aggressive, with early local recurrence, metastasis to regional and distant lymph nodes and viscera, and no response to several different chemotherapeutic regimens.


CONCLUSIONS
A careful review of the literature led us to believe that inflammatory monomorphic undifferentiated sarcoma may represent a rare and distinct clinicopathological entity that does not appear to have been previously described.
Department of Pathology, State Key Laboratory of Cancer Biology, Xijing Hospital and School of Basic Medicine, Fourth Military Medical University, Xi'an, PR China. zhwang@fmmu.edu.cn
Zhe
Z
Wang
Gaosheng
G
Huang
Qingguo
Q
Yan
Lu
L
Wang
Jin
J
Zhu
Yang
Y
Lu
Peifeng
P
Li
Hong
H
Cheng
M Joe
MJ
Ma
Bruce F
BF
Walker
Philip W
PW
Allen
D000328:Adult; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology*; D002648:Child; D017809:Fatal Outcome; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D009336:Necrosis; D010014:Osteolysis; D011859:Radiography; D012509:Sarcoma / Q000378:metabolism / Q000556:secondary* / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D035441:Thoracic Wall / Q000000981:diagnostic imaging / Q000473:pathology