Desmoid-type fibromatosis (DTF) is a benign, locally infiltrating mesenchymal tumor that causes fibroblast and myofibroblast proliferation, and increased collagen production in deep musculoaponeurotic structures. It has intermediate biological characteristics between benign fibrous lesions and fibrosarcoma (1). The disease is extremely rare, accounting for only 0.03% of all neoplasms (2). Additionally, a notable predilection towards females has been observed (3). The etiology of DTF is multifaceted, possibly influenced by a combination of genetic predisposition, traumatic events and hormonal factors (4). DTF is classified into three subtypes based on their anatomical location: Abdominal wall, intra-abdominal, and extra-abdominal. Extra-abdominal desmoid tumors account for approximately one-third of all desmoid cases and most commonly arise in the shoulder, pelvic girdle and limbs. However, only 10-25% of cases occur in the head and neck region (5). Unlike other benign neoplasms in this area, desmoid tumors exhibit infiltrative growth and a marked propensity for local recurrence following surgery, underscoring the need for accurate diagnosis and appropriate management. Although complete resection with negative microscopic margins is considered the standard of care for DTF which is unresponsive to other treatments, achieving such margins in the head and neck is challenging due to the density of vital structures. This difficulty is even more pronounced in pediatric patients, where surgeons may hesitate to perform wide resections owing to the substantial risk of post-operative functional morbidity (3,4).

The present study describes the case of a male pediatric patient diagnosed with DTF involving the level II. The present case report was written in accordance with the CaReL guidelines, with filtering references to prevent citing contents in blacklisted journals (6,7).

Herein, a literature review was also conducted to identify reports on DTF of the head and neck through a Google Scholar search using the key word ‘neck desmoid fibromatosis’. A total of 7 cases of DTF in the head and neck region were reviewed and these are summarized in Table I. Of the 7 cases, 4 patients were female and 3 patients were male, with ages ranging from 9 months to 42 years. The tumor in 4 cases was located in the neck, while the remaining tumors were found in the mandible (n=2) and tongue (n=1). Among the cases reviewed herein, the neck tumors generally progressed gradually, occasionally causing symptoms, such as numbness, pain and weakness, whereas tumors in other locations exhibited a more rapid progression. The preferred imaging modalities for these tumors were a CT scan and magnetic resonance imaging (MRI). Surgical exploration with mass excision and clear safety margins was the standard approach for managing these tumors. The majority of patients experienced uneventful outcomes following surgery, apart from 1 patient who developed temporary partial facial nerve paralysis.

DTF of the head and neck is a rare benign mesenchymal tumor with an annual incidence of 2-4 cases per million individuals (2,8). In the case series study by Hoos et al (9), a sex predilection for females was noted, whereas in the literature review performed in the study by Miyashita et al (8), including 141 pediatric patients with DTF of the head and neck aged birth to 18 years, no sex predominance was observed. In the literature review performed in the study by Miyashita et al (8), the mandible was the most common site of involvement, accounting for 25% of cases. Additional reported sites included the submandibular region, the infratemporal fossa, the neck, the peritracheal area and the paraspinal region (8).

Empirical evidence indicates that among DTFs involving the neck, the anterolateral aspect is a common site, with the majority of patients presenting with a painless mass (60-94%). However, neurogenic symptoms, such as pain or focal motor deficit may be observed in a smaller proportion of cases (16-36%) (10). Compression of the brachial plexus can result in symptoms, such as tingling, paresthesia, numbness and weakness in hand muscles (1). A rapidly enlarging DTF was also reported in a pediatric case in the study by Miyashita et al (8). The case in the present study was a 2-year-old male presenting with a painless, slow-growing swelling in the left submandibular region, which progressed over a period of 3 months.

The diagnosis of DTF in the head and neck region is primarily based on a clinical presentation, imaging studies and biopsy. While radiographs may be a useful initial diagnostic tool, their findings can vary, and a definitive diagnosis usually requires HPE (10,11). The accurate assessment of the extent of the tumor and its relation to surrounding structures is crucial for effective management. Advancing imaging techniques, such as neck CT scans and MRI, play a key role in such an assessment. MRI, in particular, is preferred for its superior soft tissue contrast, which aids in more precise tumor delineation and reduces the risk of damaging critical structures during surgery (11). Typically, DTF exhibits intermediate signal intensity on T1-weighted images (T1WIs), similar to muscle tissue, and on T2-weighted images (T2WIs), where the signal is lower than that of fat, but higher than that of adjacent muscle. Fat-suppressed T2-weighted images often exhibit increased signal intensity within these lesions. Areas with a low signal intensity within DTF correspond to regions of higher collagen content. Post-contrast imaging usually reveals moderate to marked heterogeneous enhancement, reflecting the vascularity of the lesion. In the case in the present study, a neck ultrasound revealed a well-defined, lobulated, predominantly solid hypoechoic left subcutaneous mass, measuring 38x31x27 mm, with mild vascularity. Chest and abdominal contrasted CT scans yielded normal findings.

The primary clinical differential diagnoses include soft-tissue sarcoma, lymphoma, myositis ossificans and arteriovenous malformation. Imaging often rules out the latter conditions; however, distinguishing desmoid tumors from soft tissue sarcomas can be challenging (12). Desmoid tumors exhibit a spectrum of clinical behaviors, ranging from indolent growth to aggressive local infiltration, which significantly influences management strategies. Aggressive variants, characterized by rapid growth, local invasion and a higher risk of recurrence, often require multimodal treatment. Post-operative radiation therapy (RT) is particularly considered in cases where achieving negative surgical margins is challenging or where tumors are located near critical structures, making complete excision infeasible without undue morbidity (1,13). Despite this, the role of RT remains controversial due to the benign histological nature of desmoid tumors and the potential for significant complications, coupled with a lack of prospective clinical trials assessing its efficacy in reducing recurrence rates (11,14,15). Current evidence is derived from retrospective studies, which suggest that combining RT with surgery may improve local control rates, particularly in cases where wide margins are difficult to achieve (8). Surgical resection has traditionally been the primary treatment for primary and recurrent desmoid tumors, aiming for tumor-free margins. A 5-year local control rate of 80% with negative-margin resection has been reported. However, some experts argued that achieving negative margins may lead to unnecessary complications and may not prevent local recurrence (11). The recurrence rate among pediatric patients undergoing surgery has been reported as 27.2% (8).

For benign or less aggressive variants, which demonstrate slow growth and minimal recurrence risk, a more conservative approach, such as watchful waiting, is gaining acceptance, particularly for asymptomatic cases or tumors in anatomically challenging locations. Given the challenges of balancing treatment efficacy with minimizing overtreatment or unnecessary morbidity, the management of desmoid tumors underscores the need for a multidisciplinary approach. In pediatric patients with DF that is unresponsive to non-surgical therapies, surgeons may hesitate to pursue wide resections due to the substantial risk of postoperative morbidity. When a large tumor is located near vital structures, achieving adequate surgical margins can be particularly challenging (8). The literature review performed in the study by Miyashita et al (8) revealed post-operative complications in 13 patients (10.4%). Trismus was the most frequent (n=6). A total of 2 patients developed secondary papillary carcinoma following radiation therapy. Additional complications included osteomyelitis (n=2), mild ptosis resulting from facial nerve sectioning (n=1), restricted neck mobility (n=1) and Claude-Bernard-Horner syndrome (n=1) (8). Individualized treatment planning, guided by the biological behavior of the tumor, is essential to optimize patient outcomes while addressing the limitations of current evidence and therapeutic options (10,15). In the present case report, the mass was successfully excised under general anesthesia with no complications. No recurrence was reported following 6 months of follow-up. The limitations of the present case report include the inability to retrieve the ultrasound figures due to poor archiving and CT scan figures for the case, as they were conducted at an external facility.

In conclusion, DTF of the head and neck presents a complex clinical scenario. Its rarity and the challenges associated with diagnosis, location, and treatment necessitate careful consideration, particularly in pediatric cases, in order to prevent unnecessary interventions and complications. Ongoing research is thus warranted to define standardized treatment protocols and improve therapeutic outcomes for this challenging condition.