Elastofibroma 

Updated: Apr 05, 2021
Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD 

Overview

Background

Elastofibroma is a rare, benign, slow-growing connective-tissue tumor that occurs most often in the subscapular area in elderly women.[1] Jarvi and Saxen[2] first described this rare entity, elastofibroma, in 1961. Elastofibroma is characterized by accumulated abnormal elastic fibers and is generally regarded as a reactive process, an unusual fibroblastic pseudotumor.[3]

Pathophysiology

The etiology of elastofibroma remains unclear, although prevalence is increased in persons who perform manual labor involving the shoulder girdle. Thus, repeated trauma due to mechanical friction of the scapula against the ribs has been suggested to induce this process. This theory provides an explanation for the right-sided preponderance; however, in up to 66% of cases, the tumor is bilateral. Rarely, elastofibromas may be multiple in the same individual.[4, 5] In up to one third of cases, the patient has a family history of the tumor, suggesting a nontraumatic genetic origin. A mechanical strain-dependent reactivation of periostin and tenascin-C expression, along with elastin deposition, may account for the pathogenesis of their neoplasms.[6]

Elastofibroma may be a reactive process; its etiology remains unknown.[7] In a 2002 study, chromosomal gains were suggested as a cause for elastofibromas. Nishio et al[8] detected DNA copy number changes involving 1 or 2 chromosomes in 33% of 27 patients. The most common recurrent gains were at bands Xq12-q22 and 19. High-level amplifications and recurrent losses were not observed. No correlation was found between DNA copy number changes and elastofibroma size. It was concluded that these chromosomal regions may contain genes involved in the development of at least some elastofibromas. Genomic alterations were documented in 2 cases, with losses detected on 1p, 13q, 19p, and 22q by array-based comparative genomic hybridization (aCGH).[7]

Coexistence of an elastofibroma with a high-grade spindle cell sarcoma[9] and a high-grade leiomyosarcoma[10] has been reported. Moreover, because a number of other entities, including lipomas, metastases, sarcomas, and extra-abdominal fibromatoses and hemangiomas, may occur on the back and in the subscapular site, the diagnosis must be confirmed with biopsy.[11]

Cytogenetic chromosomal instability and some recurrent or clonal chromosomal changes have raised the possibility that the lesion represents a neoplastic process.[3] Recent findings suggest that CD34-positive mesenchymal cells are an integral component of elastofibroma, presumably representing a clonal fibrous proliferation.[12]

Etiology

The histogenesis of the morphologically unique elastic fibers is controversial. Note particularly that the elastinophilic structure may result from elastotic degeneration of collagen. Recent immunohistochemical, ultrastructural, and biochemical investigations have shown that the elastinophilic material is composed of elastic fibers with only a slight difference in the amino acid composition. This elastic material possibly derives from an abnormal process of elastogenesis rather than representing degenerative changes in collagen or elastic fibers themselves.

Epidemiology

Frequency

Elastofibromas are rare. Elastofibromas are often mistaken for malignant tumors because of their size and location deep to the periscapular muscles. An orthopedic oncology database of 17,500 patients showed 15 patients with elastofibroma dorsi, 12 men and 3 women, with a mean age at diagnosis of 68.4 years and a range of 51-79 years.[13]

In another study, 1,751 patients were evaluated with (18)fludeoxyglucose (FDG) – positron emission tomography (PET)/CT scanning, which detected 29 cases of elastofibroma dorsi as an incidental finding, giving a prevalence of 1.66%.[14]

Sex

Of persons affected by elastofibromas, 93% are female.

Age

Elastofibromas occur most often in elderly women but have been reported in persons aged 35-94 years.

Prognosis

Mortality rates are unknown for elastofibroma. Morbidity is not expected.

 

Presentation

History

Elastofibroma dorsi is an uncommon benign soft tissue pseudotumor usually located at the lower pole of the scapula, deep to the serratus anterior, and often attached to the periosteum of the ribs; patients with elastofibroma dorsi present with a long history of swelling and, occasionally, pain and discomfort.[13] Sometimes, the swelling produces an elastofibroma as an unexpected finding in those unfamiliar with this entity.[1] As it is often bilateral, the contralateral site should be evaluated.[15] Half the patients in one series of 71 patients described a clunking sensation or a localized scapular swelling during movement.[16] It can be an uncommon cause of chest pain.[17]

This uncommon fibrous pseudotumor has also been described on the foot, hand, thigh, olecranon, GI tract, trachea, dorsal spine, eye, and soft palate.[18]

Physical Examination

Clinically, patients with elastofibromas usually present with a large, well-circumscribed tumor that most often does not adhere to the overlying skin. One case of ulceration has been described.[19] In 99% of cases, elastofibromas are located in the periscapular area, in relation to the latissimus dorsi, rhomboid, and serratus anterior muscles.[20] It may be bilateral.[21] Although usually asymptomatic, it may be associated with mild pain when moving the scapula.

Uncommon locations include the deltoid muscle,[22] ischial tuberosity, greater trochanter, olecranon, thoracic wall, foot, stomach, mediastinum,[23] orbita, cornea, and oral mucosa.[24] Occasionally, the tumor invades the surrounding tissues and becomes fixed to the underlying periosteum. Usually, the lesions are prominent and measure several centimeters in length; however, a small elastofibroma may be overlooked unless the patient is asked to move his or her arm laterally or anteriorly. Most patients with elastofibromas are asymptomatic. Only rarely do they report stiff shoulders, local pain with arm movement, and/or an annoying click with shoulder motion occur.[25] Potter et al reported an elastofibroma presenting in the oral cavity[26] ; Hsu et al described a case of elastofibroma oculi.[27]

 

DDx

Diagnostic Considerations

Other considerations include the following:

  • Extra-abdominal fibromatosis

  • Soft-tissue sarcoma[28]

  • Subcutaneous metastasis

  • Lipoma[29]

Differential Diagnoses

 

Workup

Imaging Studies

Elastofibromas have a typical sonographic appearance consisting of arrays of linear strands against an echogenic background.[30, 31] However, in some cases, the ultrasound pattern of an elastofibroma dorsi may be similar to the surrounding muscular tissue, and neither a clear cleavage surface nor a specific vascular pattern can be seen. In these cases, the elastofibroma may be difficult to distinguish from surrounding tissue.[32] If further delineating its borders proves difficult, then further imaging modalities should be used.[33]

Chest wall radiographic findings are usually normal; however, elevation of the scapula from the chest wall has been detected in a few cases.[34]

CT scanning and MRI reveal a lenticular, unencapsulated, soft tissue mass with skeletal muscle attenuation interspersed with strands of fat attenuation.[35, 36, 37] Small elastofibromas may be difficult to visualize on CT scans or MRIs, but they can be enhanced by the use of gadolinium. Its characteristic location (periscapular region) and specific imaging appearance on ultrasound images, CT scans, and MRIs facilitates accurate diagnosis.[38] Noninvasive techniques, especially MRI, and histologic assessment are closely correlated, so that sometimes a biopsy can be avoided.[39] The sensitivity and positive predictive value of MRI in the diagnosis of elastofibroma dorsi in a study of 15 patients were 93.3% (95% confidence interval, 68-100%) and 100% (95% confidence interval, 75.2-100%), respectively.[40]  CT scanning has a higher correlation than MRI in documenting the size of an elastofibroma.[41]

Incidental detection of bilateral elastofibroma dorsi with F-18 fluorodeoxyglucose positron emission computed tomography scanning has been described.[42, 43]

See the image below.

Elastofibroma. Hematoxylin and eosin stain. Interm Elastofibroma. Hematoxylin and eosin stain. Intermediate magnification. Courtesy of Soca1zim, via Wikimedia Commons.

Procedures

A biopsy specimen should be obtained from the affected area. The surgical excision should be large and should include skin, subcutaneous fatty tissue, and, if necessary, deeper tissue. A shave or punch biopsy is not sufficient.

Histologic Findings

The tumor grossly appears as an ill-defined mass with a white or gray-white, glistening surface.

Upon light microscopy, elastofibromas are dermal unencapsulated tumors composed of branched and unbranched elastic fibers, eosinophilic collagen bundles, and scattered fatty tissue. The elastic fibers have a degenerated, beaded appearance or are fragmented into small globules or droplets arranged in a linear pattern. The epidermis is usually unaffected. The interspersed spindle or stellate cells show a fibroblastlike appearance and were almost consistently positive for vimentin and frequently positive for CD34 and lysozyme immunohistochemically.[3] The CD105-positive vessels in elastofibromas appear to reflect active neovascularization.[44]

At an ultrastructural level, the elastic fibers appear as an irregular granular or fibrillary aggregation of electron-dense, amorphous material surrounded by microfibrils and collagen fibers. Collagen fibers are commonly incorporated within the elastic material.

Immunohistochemically, elastofibromas stain positively for vimentin but negatively for smooth muscle actin, S-100, desmin, and p53.[45] . Positive staining for factor XIIIa and CD34 in the cells forming this neoplasm implies that it originates from primitive dermal mesenchymal cells.[46]

Because of their densely fibrous nature, hypocellularity may be observed in fine-needle aspiration biopsy specimens of elastofibromas; thus, diagnostic material may be overlooked. The smears show evidence of mature adipocytes, fibroblasts, collagen fibers, globular bodies, and characteristic braidlike or fernlike structures, revealing degenerative elastic fibers. Careful evaluation of the background of the smears coupled with full knowledge of the clinical and radiological findings, including those from MRIs, is required to establish the correct diagnosis; therefore, a skin biopsy is preferable.

 

Treatment

Surgical Care

Complete local surgical excision is the treatment of choice in symptomatic patients or if malignancy cannot be excluded.[47, 48] It can be well-controlled by radical surgery.[16] Recurrence after surgery is unusual.[49] Spontaneous regression has been observed without treatment. Because malignant transformation has not been described, asymptomatic lesions need not be excised.[50] In fact, surgical resection should be limited to those who are symptomatic, as the incidence of postoperative complications is high.[51, 52]  Bilateral back elastofibroma after resection of a malignant fibrous histiocytoma has been described.[53]

Long-Term Monitoring

Because elastofibromas are benign neoplasms, no long-term follow-up care is necessary.