Nuchal fibroma should be recognized as a new extracolonic manifestation of Gardner-variant familial adenomatous polyposis

Repetitive trauma-induced extra-nuchal-type fibroma

A nuchal-type fibroma is a rare, benign fibrous tumour that typically occurs in the posterior neck along the midline, but can occur in extra-nuchal locations, most commonly in the back, shoulder and face. We present a biopsy-proven case that arose as a result of heavy gym-related activities. In particular, a heavy barbell was rested on his vertebral prominence at the level of C7/T1 during leg squatting. Repetitive trauma as a cause for extra-nuchal-type fibromas has been sparsely reported, but we suggest that sustained high pressure is an additional required feature. Although this lesion was in the posterior neck, it was contained entirely within the subcutaneous tissues without involvement of the nuchal ligament. Hence, it was considered an extra-nuchal fibroma. A description of key ultrasound and MRI imaging characteristics are provided to assist in making the diagnosis, along with a review of the current literature and a discussion of differential diagnoses.

Nuchal-type Fibroma: Single-Center Experience and Systematic Literature Review

BACKGROUND

Nuchal-type fibroma is a rare benign tumor arising from the connective tissue. Our aim was to present our experience via two cases of this tumor and a comprehensive review of the literature.

PATIENTS AND METHODS

We report a case of a 23-year-old female with a mass located in the posterior neck and the upper back and a case of a 50-year-old male with a mass located in the posterior neck, which were proved to be nuchal-type fibromas in the histopathological examination. We also searched the PubMed/Medline database for published cases of nuchal-type fibromas.

RESULTS AND DISCUSSION

Nuchal-type fibroma is a rare benign tumor arising from the connective tissue, usually in the posterior neck, which affects different ages, with most patients being male. It is a poorly circumscribed tumor consisting of hypocellular, thick, dense and haphazardly arranged collagen bundles with entrapped adipocytes, nerve fibers and muscle fascicles and a few scattered spindle cells, which are CD34 positive. Its excision is curative, and the recurrence risk is generally low. However, patients with Gardner's syndrome may experience recurrence more frequently.

CONCLUSION

Nuchal-type fibroma should be included in the differential diagnosis of subcutaneous, soft-tissue masses, especially when these involve the posterior neck.

Multiple nuchal-type fibromas on the scalp: a case report

Nuchal-type fibroma is a rare, benign, fibrous, tumor-like proliferation characterized by dense hypocellular bundles of collagen, with sparsely scattered fibroblasts, interspersed fat tissue, and entrapped nerve fibers. It usually develops in the posterior neck as a solitary, firm, poorly circumscribed, subcutaneous mass. Herein, we report about a 32-year-old man who presented with a 6-year history of multiple nodules on the scalp. Histopathological features were consistent with those of nuchal-type fibroma. The tumors were surgically excised.

Extra nuchal-type fibroma associated with elastosis, traumatic neuroma, a rare APC gene missense mutation, and a very rare MUTYH gene polymorphism: a case report and review of the literature*

We report a case of an extra nuchal-type fibroma in a 51-year-old male suspected to have attenuated familial adenomatous polyposis (Gardner's syndrome), who presented with a longstanding buttock mass excised due to enlargement and pain. Histopathologically, lobules of haphazard, hypocellular, hyalinized collagen bundles replaced the dermis and subcutis and entrapped nerve bundles, mimicking Morton neuroma. Ramifying nerve twigs found around larger nerve fascicles showed the co-existence of traumatic neuroma. Elastic tissue stain revealed elastosis characterized by large, arborizing fibers lying between and within the hyalinized collagen bundles. Modified Masson's trichrome stain showed light blue staining of collagen bundles producing the hyalinized nodules with irregular, light red staining of collagen bundles at their periphery and within tumor collagen. Compression and/or degeneration of collagen and secondary elastosis with later entrapment by tumor collagen could explain this microscopic phenotype. By immunohistochemistry, tumor spindle cells expressed nuclear β-catenin and cyclin D1, mostly within regions of fibrosis implicating activation of the adenomatous polyposis coli (APC)-Wnt pathway. Genetic analysis showed a missense mutation in APC gene (c.7504G>A, p.G2502S in exon 15) and a functional homozygous polymorphism in the MUTYH gene (c.36+325G>C, (IVS1+5G/C)). Nuchal-type fibroma has been associated with Gardner's syndrome and trauma. In this patient, genetic predisposition coupled with repetitive, localized trauma and collagen degeneration may have provided the stimulus for the development of extra nuchal-type fibroma.

Nuchal-type fibroma of the ankle: a case report

Nuchal-type fibroma is rare benign fibrous tumor that has the potential to recur. It is typically located in the subcutaneous tissues of the posterior aspect of the neck, although it can affect other anatomical sites. Extranuchal involvement occurs most commonly in the back, shoulder, and face, as well as other sites specified in single case reports. In this report, we describe the case of a patient presenting with a nuchal-type fibroma arising in the ankle. The lesion infiltrated the superior extensor retinaculum. Marginal resection was performed, and there was no evidence of recurrence after 12 months of follow-up. To our knowledge, this is the first report of a nuchal-type fibroma localized to the ankle.

Nuchal-type Fibroma of the Coccyx

Nuchal-type fibroma is a recently described, rare, tumor-like process of fibrous tissue occurring chiefly in the dorsocervical area. Nuchal-type fibromas in extranuchal locations are morphologically indistinguishable from lesions involving the nuchal region. Histopathologic findings of nuchal-type fibroma are poorly demarcated, dense collagen bundles with sparsely scattered fibroblasts, some interspersed adipose tissue, and entrapped nerve fibers. We report a patient with a mass on the coccyx area, and these were histopathologically consistent with nuchal-type fibroma. This tumor was surgically excised, and no recurrence had been noted during the two year follow-up period.

Gardner's syndrome associated fibromas

Three patients with Gardner's syndrome having benign fibrous proliferations in the soft tissues and the oral cavity are presented. Lesions in all three patients were morphologically different. Two excised lesions in Case 1 were histologically identical to nuchal-type fibroma (NTF) and one lesion in this patient was an epidermal cyst. Case 2 had a lesion located in the soft tissues of the shoulder, which was morphologically similar to NTF and, in addition, contained mildly atypical and multinucleated fibroblastic cells. The oral lesion in Case 3 looked like a fibroma and was morphologically different from all fibrous lesions that have ever been described in Gardner's syndrome. The cases in the present report show that the term Gardner's fibroma is just a descriptive name encompassing a spectrum of morphologically different benign fibrous proliferations associated with this syndrome. Therefore, the term Gardner's fibroma should not be used as a specific name for NTF arising in patients with Gardner's syndrome as suggested in the most recent WHO classification of soft tissue and bone tumors.