Nuchal Fibroma: A Clinicopathological Review

Abstract

Nuchal fibroma, or collagenosis nuchae, is a benign soft tissue tumor that arises from the posterior cervical subcutaneous tissue, with a predilection for the interscapular and paraspinal regions. Because of its benign clinical course and its close histopathologic similarity to other benign head and neck lesions, this lesion may be misdiagnosed and underreported. The purpose of this paper is to review the histopathologic and radiologic findings unique to nuchal fibroma, and compare and contrast it to the other soft tissue neoplasms within the clinical differential diagnosis. These include several benign (elastofibroma, lipoma, fibrolipoma, nodular fasciitis) and rare malignant entities (fibrosarcoma, liposarcoma, fibromatosis).

Nuchal-type fibroma of the buttock: magnetic resonance imaging findings

“…c Gadoliniumenhanced axial T1-weighted spin-echo MR image obtained with fat saturation shows mild homogeneous enhancement of the mass without a central necrotic portion (arrow). The degree of enhancement of the mass is similar to that of muscle of nuchal-type fi broma were reported as a mass with low signal intensity on both SE T1-and T2-weighted images, [4][5][6] with no signifi cant enhancement because of their dense fi brous network and minimal water content. 6 Because these tumors are not encapsulated, poorly defi ned margins and infi ltration of fat, muscle, and/or skin may be present.…”

“…The degree of enhancement of the mass is similar to that of muscle of nuchal-type fi broma were reported as a mass with low signal intensity on both SE T1-and T2-weighted images, [4][5][6] with no signifi cant enhancement because of their dense fi brous network and minimal water content. 6 Because these tumors are not encapsulated, poorly defi ned margins and infi ltration of fat, muscle, and/or skin may be present. 6 In our case, which involved a nuchal-type fi broma in the buttock, the imaging fi ndings on T1-and T2-weighted images were similar to those of the previously reported cases.…”

“…[2][3][4][5][6] In most cases, the diameter of the tumor ranges from 2.5 to 8.0 cm, although a giant nuchal-type fi broma with a maximum diameter of 16.5 cm has been reported. 4 Although the pathogenesis of nuchal-type fi broma remains unknown, it has been associated with trauma, diabetes, and Gardner's syndrome.…”

“…6 Because these tumors are not encapsulated, poorly defi ned margins and infi ltration of fat, muscle, and/or skin may be present. 6 In our case, which involved a nuchal-type fi broma in the buttock, the imaging fi ndings on T1-and T2-weighted images were similar to those of the previously reported cases. These low signal areas on T2-weighted images corresponded to areas of low cellularity with abundant collagen fi bers.…”

“…Although the clinical, histopathological, and MRI features have been well described in these reports, only a limited description of contrast-enhanced MRI fi ndings has been reported. 6 We report here on the MRI fi ndings of a nuchal-type fi broma involving the buttock, with emphasis on the different degree of enhancement of the tumor.…”