Chest Wall Fibromatosis with Congenital Muscular Torticollis: Two Forms of Deep Fibromatosis in a Child.

Desmoid tumors (fibromatosis) are intermediate grade, locally aggressive soft-tissue tumors. A rare case of chest wall fibromatosis in a girl with congenital muscular torticollis is being reported. This report also highlights the need for long-term surveillance in such cases, despite being a benign pathology.

INTRODUCTION

Chest wall fibromatosis, a form of deep fibromatosis, is a rare clinical entity in children. These tumors do not metastasize but are known for local recurrences. Congenital muscular torticollis (CMT) or “fibromatosis colli” is another form of deep fibromatosis that afflicts the sternocleidomastoid (SCM) muscle. Herein, we describe a rare coexistence of these different forms of deep fibromatosis in a 6-year-old girl with congenital torticollis of left side and chest wall desmoid tumor to highlight the importance of long-term surveillance.

CASE REPORT

A 6-year-old girl presented to us with CMT on the left side, and an incidentally detected right-sided chest wall mass, identified during evaluation for persistent dry cough. There was no history related to abnormal obstetric presentations at birth, swelling, trauma, or prior head or neck surgery.

On neck examination, torticollis was evident on the left side. A firm, nontender, 6 cm × 4 cm mass fixed to the posterior chest wall was appreciable between the fourth and sixth ribs on the right side. Preoperative chest skiagram revealed a mass arising in the right upper chest wall causing the collapse of the right upper zone. Subsequently, a contrast-enhanced computed tomography scan of the chest confirmed the presence of destructive osseous lesion involving the right fourth, fifth, and sixth ribs posteriorly [Figure 1a and b].

Figure 1

Preoperative radiological evaluation of the patient. (a) Chest skiagram (anteroposterior view) shows mass arising in the right upper chest wall causing collapse of the right upper zone and periosteal reaction in right fourth and fifth ribs. (b) Contrast-enhanced computed tomogram of chest performed for the same patient shows the presence of destructive osseous lesions of the right fourth, fifth, and sixth ribs posteriorly (shown by arrow)

A right posterolateral thoracotomy with excision of the tumor and release of the left SCM tendon was performed. The tumor was completely excised along with a portion of the fifth rib. Histopathologic examination showed dense hyalinized fibrocollagenous tissue with bone and focal pseudocartilaginous areas. The tumor was attached to the periosteum of the fifth rib, but margins were free. Immunohistochemistry [Figure 2] revealed no features of epidermal (S100 negative) or smooth muscle differentiation (SMA negative). CD 34 and CD 56 were also negative. Based on these findings, a diagnosis of a desmoid tumor was made.

Figure 2

(a and b) Micrograph of the tumor - (H and E, × 40) spindle cells with slender nuclei and dark eosinophilic cytoplasm are arranged in bundles. It also shows tumor infiltration into adjacent adipose tissue and skeletal muscle. (c-f) Immunohistochemistry of the tumor - negative immunostaining for CD34, CD56, S100, and SMA is seen in c-f respectively

DISCUSSION

CMT is a musculoskeletal disorder manifesting with head tilt due to shortening of the SCM muscle. It has an incidence of 0.3%–1.2% with a slight male predominance. Its exact etiology is unknown, but the degeneration of SCM muscle fibers and fibrosis is often noticed in the resected specimens.[1] Children with CMT can be divided into three clinical subgroups. Group 1 (sternomastoid tumor group) – there is the presence of palpable swelling in the body of sternomastoid muscle. Group 2 consists of children having tightness in the sternomastoid muscle without a palpable tumor (index case belongs to this group). Group 3 or postural torticollis group has children without a palpable mass or tightness.[2] Conservative management with physical therapy, surgery, or a combination of both may be necessary for its successful correction.

Fibromatosis refers to a group of locally aggressive soft-tissue tumors with the proliferation of well-differentiated fibroblasts, the absence of cytological and clinically malignant features but common tendency to cause local recurrence. It can be further classified into superficial (fascial) or deep (musculoaponeurotic). The superficial form has small, slow-growing lesions arising from the superficial fascia. It includes palmar fibromatosis (Dupuytren's disease), plantar fibromatosis (Ledderhose disease), and infantile digital fibromatosis. In contrary, the “deep” form consists of large-sized, rapidly growing, and aggressive tumors. Fibromatosis colli, extra-abdominal desmoid tumor, and aggressive infantile fibromatosis are common types of deep fibromatoses.

Desmoid tumors are regarded as a group of intermediate grade tumors. They represent 0.03% of all neoplasms in children. A desmoid tumor can occur anywhere in the body. Over half of these tumors involve the extremities. Chest wall represents 8%–10% of all desmoid tumors.[3] The exact etiology remains unclear. However, association with mutations in adenomatous polyposis colli gene and dysregulation in the beta-catenin pathway is commonly seen.

Grossly, these tumors are solid non encapsulated masses. Microscopically, they have bland appearing well-differentiated fibroblasts cells with a fibrous stroma. Immunohistochemistry reveals tumor cells staining diffusely for vimentin, and sometimes for smooth muscle actin. The absence of desmin, S-100, and CD34 is frequently illustrated.[4] Gross total resection is the mainstay of treatment. Recurrence rates are variable and may be as high as 87% in tumors arising at extra-abdominal sites.[5] Local recurrence is usually seen within 12–18 months of surgery. The best predictor of recurrence and event-free survival is negative margins of the resected tumor.[6] Adjuvant therapy is reserved for recurrent and residual disease. Chemotherapeutic agents including cytotoxic drugs such as doxorubicin, vincristine, dactinomycin, and cyclophosphamide have been utilized in combination regimens. Noncytotoxic agents such as nonsteroidal anti-inflammatory drugs (NSAIDs) and anti-estrogen therapy have also shown their efficacy in desmoid tumors.

In our case, the child had two different forms of deep fibromatosis, i.e., fibromatosis colli and chest wall fibromatosis as a rare coincidence. The co-occurrence highlights the possible tendency of this child to fibromatosis, and this may be a subtle marker for recurrences in future. We intend to closely follow-up the child for recurrences and reserve the various pharmacological and surgical options for recurrences.

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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.