The fake fat phenomenon in organizing pleuritis: A source of confusion with desmoplastic malignant mesotheliomas

Andrew Churg, Philip Cagle, Thomas V. Colby, Joseph M. Corson, Allen R. Gibbs, Samuel Hammar, Nelson Ordonez, Victor L. Roggli, Henry D. Tazelaar, William D. Travis, Mark Wick

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We report 9 patients with pleural biopsies referred because of concern about infiltration of what appeared to be chest wall fat by pan-keratin-positive spindled cells, a finding that led to a consideration of desmoplastic mesothelioma. All patients showed pleural effusions/pleural thickening on computed tomographic scan. Pleural biopsy showed a greatly thickened and fibrotic paucicellular pleura with circular fat-like spaces and, sometimes, adjacent oblate spaces mostly deep in the fibrotic area. Indistinct, keratin-positive, spindle cells arranged parallel to the pleural surface coursed between these fat-like spaces. S-100 stains were negative around the fat-like spaces. Vimentin stains showed that the spaces did not have a cellular lining of any kind. Sometimes the spaces contained faintly hematoxyphilic material that was Alcian blue positive, and similar material was seen in the fibrotic stroma. Follow-up with periods ranging from 6 to 30 months revealed that 8 cases had stable disease on chest imaging or by clinical findings. One case had slowly progressive pleural thickening. These observations suggest that spaces resembling fat may be encountered in fibrotic pleurae and that horizontally oriented keratin-positive spindled cells between the fat-like spaces deep in the fibrotic portion of a thickened pleura represent a benign finding seen in some cases of organizing pleuritis/fibrothorax. The spaces themselves are probably artifacts derived from the biopsy procedure and/or cutting artifacts. In contrast, in true desmoplastic mesotheliomas there is downward, rather than horizontal, growth of keratin-positive spindled cells running between clearly definable fat cells.

Original languageEnglish (US)
Pages (from-to)1823-1829
Number of pages7
JournalAmerican Journal of Surgical Pathology
Volume35
Issue number12
DOIs
StatePublished - Dec 2011

Fingerprint

Pleurisy
Keratins
Fats
Pleura
Mesothelioma
Biopsy
Adipocytes
Artifacts
Coloring Agents
Alcian Blue
Thoracic Wall
Vimentin
Pleural Effusion
Thorax
Malignant Mesothelioma
Growth

Keywords

  • adipose tissue
  • desmoplastic malignant mesothelioma
  • organizing pleuritis

ASJC Scopus subject areas

  • Anatomy
  • Pathology and Forensic Medicine
  • Surgery

Cite this

The fake fat phenomenon in organizing pleuritis : A source of confusion with desmoplastic malignant mesotheliomas. / Churg, Andrew; Cagle, Philip; Colby, Thomas V.; Corson, Joseph M.; Gibbs, Allen R.; Hammar, Samuel; Ordonez, Nelson; Roggli, Victor L.; Tazelaar, Henry D.; Travis, William D.; Wick, Mark.

In: American Journal of Surgical Pathology, Vol. 35, No. 12, 12.2011, p. 1823-1829.

Research output: Contribution to journalArticle

Churg, A, Cagle, P, Colby, TV, Corson, JM, Gibbs, AR, Hammar, S, Ordonez, N, Roggli, VL, Tazelaar, HD, Travis, WD & Wick, M 2011, 'The fake fat phenomenon in organizing pleuritis: A source of confusion with desmoplastic malignant mesotheliomas', American Journal of Surgical Pathology, vol. 35, no. 12, pp. 1823-1829. https://doi.org/10.1097/PAS.0b013e31822a2481
Churg, Andrew ; Cagle, Philip ; Colby, Thomas V. ; Corson, Joseph M. ; Gibbs, Allen R. ; Hammar, Samuel ; Ordonez, Nelson ; Roggli, Victor L. ; Tazelaar, Henry D. ; Travis, William D. ; Wick, Mark. / The fake fat phenomenon in organizing pleuritis : A source of confusion with desmoplastic malignant mesotheliomas. In: American Journal of Surgical Pathology. 2011 ; Vol. 35, No. 12. pp. 1823-1829.
@article{75c68cd7d1fa4c6ba0078df1d5c90c08,
title = "The fake fat phenomenon in organizing pleuritis: A source of confusion with desmoplastic malignant mesotheliomas",
abstract = "We report 9 patients with pleural biopsies referred because of concern about infiltration of what appeared to be chest wall fat by pan-keratin-positive spindled cells, a finding that led to a consideration of desmoplastic mesothelioma. All patients showed pleural effusions/pleural thickening on computed tomographic scan. Pleural biopsy showed a greatly thickened and fibrotic paucicellular pleura with circular fat-like spaces and, sometimes, adjacent oblate spaces mostly deep in the fibrotic area. Indistinct, keratin-positive, spindle cells arranged parallel to the pleural surface coursed between these fat-like spaces. S-100 stains were negative around the fat-like spaces. Vimentin stains showed that the spaces did not have a cellular lining of any kind. Sometimes the spaces contained faintly hematoxyphilic material that was Alcian blue positive, and similar material was seen in the fibrotic stroma. Follow-up with periods ranging from 6 to 30 months revealed that 8 cases had stable disease on chest imaging or by clinical findings. One case had slowly progressive pleural thickening. These observations suggest that spaces resembling fat may be encountered in fibrotic pleurae and that horizontally oriented keratin-positive spindled cells between the fat-like spaces deep in the fibrotic portion of a thickened pleura represent a benign finding seen in some cases of organizing pleuritis/fibrothorax. The spaces themselves are probably artifacts derived from the biopsy procedure and/or cutting artifacts. In contrast, in true desmoplastic mesotheliomas there is downward, rather than horizontal, growth of keratin-positive spindled cells running between clearly definable fat cells.",
keywords = "adipose tissue, desmoplastic malignant mesothelioma, organizing pleuritis",
author = "Andrew Churg and Philip Cagle and Colby, {Thomas V.} and Corson, {Joseph M.} and Gibbs, {Allen R.} and Samuel Hammar and Nelson Ordonez and Roggli, {Victor L.} and Tazelaar, {Henry D.} and Travis, {William D.} and Mark Wick",
year = "2011",
month = "12",
doi = "10.1097/PAS.0b013e31822a2481",
language = "English (US)",
volume = "35",
pages = "1823--1829",
journal = "American Journal of Surgical Pathology",
issn = "0147-5185",
publisher = "Lippincott Williams and Wilkins",
number = "12",

}

TY - JOUR

T1 - The fake fat phenomenon in organizing pleuritis

T2 - A source of confusion with desmoplastic malignant mesotheliomas

AU - Churg, Andrew

AU - Cagle, Philip

AU - Colby, Thomas V.

AU - Corson, Joseph M.

AU - Gibbs, Allen R.

AU - Hammar, Samuel

AU - Ordonez, Nelson

AU - Roggli, Victor L.

AU - Tazelaar, Henry D.

AU - Travis, William D.

AU - Wick, Mark

PY - 2011/12

Y1 - 2011/12

N2 - We report 9 patients with pleural biopsies referred because of concern about infiltration of what appeared to be chest wall fat by pan-keratin-positive spindled cells, a finding that led to a consideration of desmoplastic mesothelioma. All patients showed pleural effusions/pleural thickening on computed tomographic scan. Pleural biopsy showed a greatly thickened and fibrotic paucicellular pleura with circular fat-like spaces and, sometimes, adjacent oblate spaces mostly deep in the fibrotic area. Indistinct, keratin-positive, spindle cells arranged parallel to the pleural surface coursed between these fat-like spaces. S-100 stains were negative around the fat-like spaces. Vimentin stains showed that the spaces did not have a cellular lining of any kind. Sometimes the spaces contained faintly hematoxyphilic material that was Alcian blue positive, and similar material was seen in the fibrotic stroma. Follow-up with periods ranging from 6 to 30 months revealed that 8 cases had stable disease on chest imaging or by clinical findings. One case had slowly progressive pleural thickening. These observations suggest that spaces resembling fat may be encountered in fibrotic pleurae and that horizontally oriented keratin-positive spindled cells between the fat-like spaces deep in the fibrotic portion of a thickened pleura represent a benign finding seen in some cases of organizing pleuritis/fibrothorax. The spaces themselves are probably artifacts derived from the biopsy procedure and/or cutting artifacts. In contrast, in true desmoplastic mesotheliomas there is downward, rather than horizontal, growth of keratin-positive spindled cells running between clearly definable fat cells.

AB - We report 9 patients with pleural biopsies referred because of concern about infiltration of what appeared to be chest wall fat by pan-keratin-positive spindled cells, a finding that led to a consideration of desmoplastic mesothelioma. All patients showed pleural effusions/pleural thickening on computed tomographic scan. Pleural biopsy showed a greatly thickened and fibrotic paucicellular pleura with circular fat-like spaces and, sometimes, adjacent oblate spaces mostly deep in the fibrotic area. Indistinct, keratin-positive, spindle cells arranged parallel to the pleural surface coursed between these fat-like spaces. S-100 stains were negative around the fat-like spaces. Vimentin stains showed that the spaces did not have a cellular lining of any kind. Sometimes the spaces contained faintly hematoxyphilic material that was Alcian blue positive, and similar material was seen in the fibrotic stroma. Follow-up with periods ranging from 6 to 30 months revealed that 8 cases had stable disease on chest imaging or by clinical findings. One case had slowly progressive pleural thickening. These observations suggest that spaces resembling fat may be encountered in fibrotic pleurae and that horizontally oriented keratin-positive spindled cells between the fat-like spaces deep in the fibrotic portion of a thickened pleura represent a benign finding seen in some cases of organizing pleuritis/fibrothorax. The spaces themselves are probably artifacts derived from the biopsy procedure and/or cutting artifacts. In contrast, in true desmoplastic mesotheliomas there is downward, rather than horizontal, growth of keratin-positive spindled cells running between clearly definable fat cells.

KW - adipose tissue

KW - desmoplastic malignant mesothelioma

KW - organizing pleuritis

UR - http://www.scopus.com/inward/record.url?scp=81355146732&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=81355146732&partnerID=8YFLogxK

U2 - 10.1097/PAS.0b013e31822a2481

DO - 10.1097/PAS.0b013e31822a2481

M3 - Article

C2 - 21959310

AN - SCOPUS:81355146732

VL - 35

SP - 1823

EP - 1829

JO - American Journal of Surgical Pathology

JF - American Journal of Surgical Pathology

SN - 0147-5185

IS - 12

ER -