College of American Pathologists
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2009 —June Case of the Month

Updated May 19, 2009


CAP Foundation June 2009 Online Case of the Month

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After reading the summary, try answering the three related multiple-choice questions below.

A 60-year-old woman had an ill-defined, rubbery and fibrous, subscapular mass adherent to the posterior chest wall (8 cm in size).

Archive Case and Diagnosis: This case first appeared as Performance Improvement Program in Surgical Pathology (PIP) 2006, Case 13 and is an Elastofibroma.

Criteria for Diagnosis and Comments:

Your slides consist predominantly of paucicellular, slightly myxoid fibrous tissue, in some areas patternless, elsewhere with thick collagen bundles haphazardly arranged. Interwoven are large, deeply eosinophilic, degenerated elastic fibers, some linearly arranged, others fragmented, all with the characteristic serrated outlines variously referred to as "petaloid", "beads on a string", "fern-like", "moth-eaten" or "Chenille (caterpillar-like) bodies". Elastic stains strikingly highlight these features as well as the sheer number of elastic fibers present that are not as evident on routine H & E stain. It also showcases the typical dense central core of these abnormal elastic fibers. Areas of preexisting adipose tissue can be seen within the lesion. These lesions stain with vimentin but are negative for smooth muscle actin, desmin and S100.

Elastofibroma was first reported in 1961 by Jarvi, et al. Greater than 93% occur in women who are usually older than 55. It presents as a painless, unilateral, slow growing, lower subscapular mass deep to the rhomboid and latissimus dorsi muscles where it is adherent to chest wall especially in the region of the 7th and 8th ribs where it may be fixed to underlying periosteum. Most patients are relatively asymptomatic, presenting with a painless swelling and often with an annoying clicking sensation when the arm is moved. Bilaterality is unusual but is being detected more often with the advent of higher resolution imaging techniques. Some patients give a history of hard manual labor involving the shoulder girdle possibly accounting for the right-sided predominance of this lesion. Rare cases have been reported in unusual locations including stomach, in which it was associated with peptic ulceration, and rectum.

Current theory suggests this lesion to be a degenerative, non-neoplastic pseudotumor arising as a result of excessive collagen deposition and abnormal elastogenesis secondary to ongoing friction between the inferior edge of the scapula and the chest wall, rather than simply degeneration of pre-existing elastic fibers. Some propose disturbed elastic fibrillogenesis by periosteal-derived cells Some have suggested a genetic predisposition to this condition, although the etiology still remains controversial because; it only affects a small percent of manual laborers; there are reports of a familial incidence (particularly in Okinawa, Japan); and reported cases with multiple lesions in odd locations,. Elastofibroma is a benign condition and is cured with surgical excision with no tendency to recur.

The classical location of this lesion in an elderly woman should easily point to the correct diagnosis in most cases, with other considerations easily excluded. Although spindle cell lipoma shares a similar location with elastofibroma (shoulder and posterior neck), it both favors men and displays characteristic thick collagen fibers intermixed with characteristic spindled mesenchymal cells. Nuchal-type fibroma, which may also enter the differential of shoulder/neck tumors, consists primarily of dense, hypocellular, elastic-poor fibrous tissue entrapping islands of indigenous adipose and nerve tissue. Some cases may be associated with Gardner syndrome. Neurofibroma, particularly the myxoid variant, may also be considered but is easily excluded by its typical elongated, wavy nuclei and S100 positive fibers. Desmoid-type fibromatosis, while sharing poor margination with elastofibroma, is more cellular and is invariably associated with skeletal muscle whereas elastofibroma does not invade muscular tissues. Finally, fibrolipoma and scar could be considered but neither contains the characteristic beaded elastic tissue structures.

Supplementary Questions For each of the following, select the most likely diagnosis from the diagnostic set (an answer may be used once, more than once, or not at all).

Question Diagnostic Set
1. Which lesion is occasionally associated with Gardner Syndrome? A. Elastofibroma
B. Histology
C. Neurofibroma
D. Nuchal-type fibroma
E. Scar
F. Spindle cell lipoma
2. Which lesion favors the shoulder and posterior neck of middle-aged men? A. Elastofibroma
B. Histology
C. Neurofibroma
D. Nuchal-type fibroma
E. Scar
F. Spindle cell lipoma
3. Which lesion contains increased and abnormal elastic fibers? A. Elastofibroma
B. Histology
C. Neurofibroma
D. Nuchal-type fibroma
E. Scar
F. Spindle cell lipoma


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  2. Goldblum JR, Beals T, Weiss SW. Elastofibromatous change of the rectum. A lesion mimicking amyloidosis. Am J Surg Pathol. 1992;16:793-795.
  3. Jarvi OH, Saxen E. Elastofibroma dorsi. Acta Pathol Microbiol Scand Suppl. 1961;144:83-84.
  4. Kransdorf MJ, Meis JM, Montgomery E. Elastofibroma: MR and CT appearance with radiologic-pathologic correlation, Am J Roentgenol. 1992;159:575-579.
  5. Kumaratilake JS, Krishnan R, Lomax-Smith J, Cleary EG. Elastofibroma: disturbed elastic fibrillogenesis by periosteal-derived cells? An immunoelectron microscopic and in situ hybridization study. Hum Pathol. 1991;22:1017-1029.
  6. Pyne D, Mootoo R, Bhanji A, Amin S. Elastofibroma dorsi. Ann Rheum Dis. 2002;61:278-279.
  7. Shimizu S, Yasui C, Tateno M, et al. Multiple elastofibromas. J Am Acad Dermatol. 2004;50:126-129.
  8. Weiss SW, Goldblum JR. Soft Tissue Tumors. 4th edition. St. Louis, MO: Mosby; 2001.
Arthur R. Cohen, MD
Surgical Pathology Committee
Presbyterian Hospital
Charlotte, NC