Myofibroma of the cheek: a case report.
Myofibromas are benign mesenchymal tumors that are commonly found in the dermis and subcutaneous tissues of the head and neck. Although most lesions are recognized during infancy and early childhood, several cases have been reported in older children and adults. We describe the case of a 9-year-old girl who presented with a solitary nodule in the left cheek and a history of minor trauma. Preoperative imaging detected the presence of a subcutaneous soft-tissue mass consistent with a soft-tissue neoplasm rather than a hematoma. Analysis of fine-needle aspiration material was nondiagnostic. Incisional biopsy revealed that the lesion was a myofibroma.
Myofibromas are mesenchymal tumors that are commonly found in the dermis or subcutaneous tissue and rarely found in muscle or bone. (1) First described by Stout (2) in 1954 and further classified by Chung and Enzinger (1) in 1981, infantile myofibromas are characterized histologically by a proliferation of fibroblasts and myofibroblasts. Immunohistochemical stains are positive for smooth-muscle actin and vimentin and negative for desmin and S-100 protein.
Infantile myofibromatosis is generally considered to be a benign process, unlike aggressive fibromatusis and fibrosarcomas, which are invasive lesions with metastatic potential. Nonetheless, bony destruction may occur in myofibromatosis, and some authors have described aggressive and infiltrative lesion behavior. (3) There are three types of infantile myofibromas: solitary myofibroma, multicentric fibromatosis without visceral involvement, and multicentric fibromatosis with visceral involvement. The prognosis is good for patients with a solitary myofibroma or multicentric myofibromatosis without visceral involvement because these lesions often regress spontaneously. Conversely, myofibromatosis with visceral involvement can be fatal within days or weeks of birth, usually as a result of pulmonary or gastrointestinal involvement. (4)
Although the vast majority of myofibromas are identified during infancy and early childhood, a number of cases have been reported in older children and adults. (5-7) A positive family history is often present in these cases, although both autosomal-dominant and autosomal-recessive transmission have been described.
Solitary nodules and diffuse myofibromatosis usually occur in the head and neck, and there is a male preponderance. (4,8) Lesions are typically painless and range in size from 0.5 to 7.0 cm. Superficial tumors usually present as palpable, rubbery, firm nodules that are freely mobile, while deeper lesions are typically fixed. Overlying skin changes, such as a purplish discoloration similar to a hemangioma, may be present. Ulceration and skin atrophy have also been described. (9)
The nonspecific nature of the clinical presentation and the relative rarity of myofibromas present a diagnostic challenge. Even when a pathologic specimen has been obtained, these lesions continue to elude diagnosis because many other lesions display areas of myofibroblastic cells. Other cutaneous and subcutaneous lesions that are considered in the differential diagnosis include leiomyoma, hemangiopericytoma, fibrous hamartoma of infancy, cutaneous inflammatory pseudotumor, desmoid tumor, nodular fasciitis, plexiform fibrohistioeytic tumor, neurofibroma, and dermatomyofibroma. (9,10)
In this article, we describe a case of solitary myofibroma that was unusual with respect to its anatomic location, its possible association with trauma, and the patient's age at presentation.
A 9-year-old Hispanic girl was referred to the otolaryngology clinic at New York Presbyterian Hospital for evaluation of a left-sided facial mass. Her history was significant for minor blunt trauma to the involved area, which she had sustained while playing soccer 2 months earlier. At first, the trauma had caused only a slight bruise, which quickly resolved. However, 2 weeks following the incident, she developed acute erythema and edema over the left malar area. She reported no associated symptoms of tenderness, fever, visual abnormalities, diplopia, bleeding, or a change in facial sensation. Her medical history was significant for mild asthma, and she had no personal or family history of similar lesions.
On initial examination, the patient was noted to be active and otherwise healthy. The subcutaneous mass in the left malar area measured 1.5 x 1.0 cm and was firm on palpation (figure 1). Fibrosis and attachment to the underlying maxilla with some darkening of the overlying skin was evident. No associated tenderness, erythema, or fluctuance was present. Findings on the remainder of her head and neck evaluation--which included cervical and cranial nerve examinations and flexible liberoptic laryngoscopy--were normal. Computed tomography (CT) of the face with intravenous contrast demonstrated a 1.8 x 1.0-cm, minimally enhancing subcutaneous soft-tissue mass without bony involvement (figure 2). This finding was consistent with the presence of a benign soft-tissue neoplasm (as opposed to a hematoma).
[FIGURES 1-2 OMITTED]
Given the benign clinical and radiographic appearance of the lesion and the apparent reliability of the patient's family, the lesion was observed for 2 months on an outpatient basis. At the 2-month follow-up, there was no clinical change in the lesion; repeat CT confirmed the absence of significant change. Analysis of fine-needle aspiration material revealed minimal cellularity and was nondiagnostic. The patient was subsequently taken to the operating room for an incisional biopsy under general anesthesia. A sublabial approach to the anterior wall of the maxilla was taken, and the lesion was partially excised. The excised portion was grossly firm and pink-tan. Given the unclear etiology of the lesion, a complete resection--which would have involved either facial incisions or potential damage to the orbit or infraorbital nerve--was deferred until a definitive diagnosis could be made.
Pathologic analysis of the excised specimen revealed primitive fibroblastic and myofibroblastic cell proliferation with infiltration into the skeletal and adipose tissue (figure 3). There was no evidence of cellular atypia and no identifiable mitosis. Immunohistochemical staining was positive for vimentin and smooth-muscle actin and negative for desmin, myogcum, and lymphoid markers.
[FIGURE 3 OMITTED]
Postoperative treatment with systemic antibiotics and steroids did not result in any change in the size of the residual lesion. At the 2-year follow-up, the lesion continued to remain stable.
Infantile myofibromas are unusual lesions that involve the head and neck in approximately one-third of cases. The most common sites are the skull, scalp, and oral cavity, but cases involving the nose, pinna, and ear canal have also been reported. (4,10-12)
Clinical characteristics. Our case was unusual in several respects. Specifically, the anatomic location, age at presentation, and possible relationship to trauma that characterized this case are not usually seen in cases of myofibroma.
Location. A review of the literature identified only a small number of cases of solitary myofibromas that involved the cheek or face. In 1981, Chung and Enzinger published a review of 61 cases of infantile myofibromatosis and described only 2 patients with a solitary myofibroma of the cheek or parotid area. (1) Only 4 other cases of isolated myofibroma of the cheek or face have been reported. (3, 5, 6, 13)
Age. Most cases of myofibroma occur in infants; presentation in older children and in adults is rare.
Trauma. A history of trauma is not typically associated with myofibromas; only sporadic cases have been reported. (14) It is interesting that our patient reported a history of minor blunt trauma to the site 2 months prior to presentation. This raises the possibility that her myofibroblastic lesion represented an exuberant reactive process. On the other hand, it is also possible that the trauma was a coincidental occurrence that merely drew attention to a pre-existing myofibromatous lesion. Also, the possibility that a myofibroma could occur as a reaction to local trauma would not explain the multiple lesions that are seen in patients with diffuse myofibromatosis.
Histologic features. Myofibromas are histologically characterized by the presence of myofibroblastic spindle cells arranged in bundles or fascicles, often with areas of extensive hyalinization. Extensive vascularity may resemble hemangiopericytoma. Similarly, vascular proliferation, myxoid stroma, and fascicular spindle growth may be seen in organizing granulation tissue, early keloid nodules, and solitary myofibromas.
There is evidence to suggest that myofibroblasts also play a role in scar formation. (15) The histologic similarity between myofibromas and scar tissue suggests that myofibromas may be the result of a self-limited reactive process rather than true neoplasms.
Diagnosis. Myofibromas present an ongoing diagnostic challenge. Routine radiologic imaging is often nondiagnostic, and findings can differ depending on the location of the lesion. Soil-tissue lesions are difficult to distinguish from other mesenchymal tumors. In our case, CT of the maxillary region showed a nonspecific, benign, soft-tissue mass that was indistinguishable from a hematoma. In a review of 13 cases of pediatric myofibromatosis, Beck et al typically characterized lesions as heterogenous masses that reflected both cystic and solid areas on CT. (3)
Other imaging modalities may help narrow the differential diagnosis. Ultrasonography of such a lesion may yield a hypoechoic region with or without a cystic space. Magnetic resonance imaging typically demonstrates isodensity to muscle on noncontrast T1-weighted imaging and hyperintensity on T2-weighted imaging. (16) Additionally, myofibromas with increased vascularity enhance with gadolinium. (16) Even with radiologic evidence, biopsy is ultimately necessary to make a definitive diagnosis and to rule out a more aggressive neoplasm.
Management. The management of myofibromas is not standardized. The appropriate treatment varies according to the clinical situation. In cases of isolated lesions, especially in infancy, expectant management is adequate because these lesions typically involute during the first 2 years of life. (4)
We performed an incisional biopsy after our patient had undergone CT, a nondiagnostic fine-needle aspiration biopsy, and 2 months of outpatient observation. We were able to excise most of the lesion, but a complete excision was precluded because of the potential risk to the orbit and infraorbital nerve. A conservative management strategy that is limited to obtaining a diagnostic biopsy sample is considered to be sufficient unless the lesion has caused a functional impairment or cosmetic deformity. Complete surgical excision should be undertaken in cases of symptomatic visceral lesions. In some cases, intimate involvement of vital structures may dictate a more conservative excision. In cases where surgery might cause major morbidity, chemotherapy is an option for reducing the size of the lesion and alleviating associated symptoms. (3)
Recurrence rates for solitary myofibromas are low. Risk factors for recurrence include a location on the extremities, age greater than 5 years at presentation, and a previous incomplete excision. (9)
(1.) Chung EB, Enzinger FM. Infantile myofibromatosis. Cancer 1981;48:1807-18.
(2.) Stout AP. Juvenile fibromatosis. Cancer 1954;7:953-78.
(3.) Beck JC, Devaney KO, Weatherly RA, et al. Pediatric myofibromatosis of the head and neck, Arch Otolaryngol Head Neck Surg 1999;125:39-44.
(4.) Fibrous tumors of infancy and childhood. In: Enzinger FM. Weiss SW. Soft Tissue Tumors. 3rd ed. St. Louis: Mosby, 1995:357-63.
(5.) Sleeman DJ, Eveson JW. Solitary infantile myofibroinatosis. Br J Oral Maxillofac Surg 1991 ;29:277-8.
(6.) Guitart J, Ritter JH. Wick MR. Solitary cutaneous myofibromas in adults: Report of six cases and discussion of differential diagnosis. J Cutan Pathol 1996:23:437-44.
(7.) Wolfe JT III, Cooper PH. Solitary cutaneous "infantile" myofibroma in a 49 year-old woman. Hum Patho1 1990;21:562-4.
(8.) Shields CL, Husson M, Shields JA, et al. Solitary intraosseous infantile myofibroma of the orbital roof. Arch Ophthalmol 1998;116: 1528-30.
(9.) Wyatt AJ, Hansen RC. Pediatric skin tumors. Pediatr Clin North Am 2000:47:937-63.
(10.) Hogan SK Salassa JR. Recurrent adult myofibromatosis. A case report. Am J Clin Pathol 1992;97:810-14.
(11.) Walsh RM, Leen EJ, Gleeson MJ. Solitary infantile and adult myofibromatosis of the nasal cavity: A report of two cases. J Laryngol Otol 1996;110:574-7.
(12.) Balakrishnan R, Pujary K, Shah P, Hazarika P. Solitary adult myofibroma of the pinna. J Laryngol Otol 1999;113:155-7.
(13.) Fletcher CD, Achu P, Van Noorden S, McKee PH. Infantile myofibromatosis: A light microscopic, histochemical and immunohistochemical study suggesting true smooth muscle differentiation. Histopathology 1987;11:245-58.
(14.) Smith KJ, Skelton HG, Barrett TL, el al. Cutaneous myofibroma. Mod Pathol 1989:2:603-9.
(15.) Terris DJ. Dynamics of wound healing, In: Bailey B J, ed. Atlas of Head and Neck Surgery--Otolaryngology. 2nd ed. Philadelphia: Lippincott-Raven, 1996:223-32.
(16.) Kayes AV, Bancroft LW. Tennyson GS, O'Connor MI. Myolibroma of the upper arm in a 52-year-old woman. Skeletal Radiol 2002;31: 240-5.
From the Department of Otolaryngology--Head and Neck Surgery, New York Presbyterian Hospital--Weill Medical College of Cornell University, New York City.
Reprint requests: Ashutosh Kacker, MD, 445 E. 77th St., Apartment 3B, New York, NY 10021. Phone: (212) 746-1485; fax: (212) 746-2253; e-mail: firstname.lastname@example.org
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|Publication:||Ear, Nose and Throat Journal|
|Date:||Jun 1, 2004|
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