Soft Tissue
Other tumors
Proximal type

Author: Vijay Shankar, M.D.

Revised: 31 January 2018, last major update December 2014

Copyright: (c) 2002-2018,, Inc.

PubMed Search: Soft tissue proximal type[title]

Related topics: Epithelioid sarcoma, Cutaneous

Page views in 2018: 563
Page views in 2019 to date: 347
Cite this page: Shankar, V. Proximal type. website. Accessed June 25th, 2019.
Definition / general
  • First described in 1997 (Am J Surg Pathol 1997;21:130)
  • Arises in soft tissue of proximal limbs or trunks
  • Frequently with epithelioid features and rhabdoid phenotype
  • Worse prognosis than "distal" type (Mod Pathol 2001;14:655)
  • May be variant of extrarenal malignant rhabdoid tumor
  • Aggressive behavior; metastases frequently lead to death
Case reports
Gross images
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Pubic tumor with ill defined multinodular masses

Microscopic (histologic) description
  • Composed primarily of large epithelioid cells with more atypia than classic epithelioid sarcoma
  • Resembles rhabdoid tumor due to intracytoplasmic hyaline inclusions
  • Large areas of necrosis and a multinodular pattern are common, but a granuloma-like pattern is uncommon
Microscopic (histologic) images

Images hosted on Pathout server:
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Keratin, courtesy of Dr. Mark R. Wick

Courtesy of Dr. Mark R. Wick

Case of the Week #69
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Large areas of necrosis

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Infiltrative margins

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Granuloma-like areas

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Rhabdoid-like cells

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PLAP negative

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Perineal soft tissue mass

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Chest wall

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Keratin, CD34, neurofilament and p53

Positive stains
Negative stains
Differential diagnosis
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