Myositis ossificans traumatica of sternocleidomastoid muscle presenting as cervical lymph-node metastasis

Int. J. Oral Maxillofac. Surg. 1995:24:170-173 Printed in Denmark. All rights reserved

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Myositis ossificans traumatica of sternocleidomastoid muscle presenting as cervical lymph-node metastasis

Julia A.Woolgar 1, d. C. Beirne 2, A. Triantafyllou 1 ~University of Liverpool School of Dentistry, and 2Regional Centre for Maxillofacial Surgery, Walton Hospital, Liverpool, UK

J. A. IVoolgar, J. C. Beirne, A. Triantafyllou: 3lyositis ossificans traumatica o f sternocleidomastoid musele presenting as cervical lymph-node metastasis, hzt. J. Oral Maxillofae. Surg. 1995; 24: 170-173. © Munksgaard, 1995 Abstract. It is well known that clinical assessment of the metastatic status o f the cervical lymph nodes in patients with squamous cell carcinoma of the upper aerodigestive tract is frequently inaccurate, and several causes for false-positive assessments are well described. We report a novel cause, namely, a case of myositis ossificans traumatica of the sternocleidomastoid muscle, which presented as a neck mass after a direct laryngoscopy for biopsy of a laryngeal squamous cell carcinoma. The importance o f this lesion is that it should be considered in the clinical differential diagnosis o f swellings in the neck.

Inaccurate clinical assessment o f the metastatic status of the cervical lymph nodes is a well-recognized problem in the management o f patients with squamous cell carcinoma o f the upper aerodigestive tract 7, and the reported incidence of false-positive assessments ranges from 8 to 56% 2"5. N o n m e t a static enlargement o f lymph nodes, salivary gland disorder, or misinterpretation of normal anatomic structures are well-recognized problems, accounting for most false-positive assessments 7. Nevertheless, clinicians should be alert to other possible sources of confusion. For this reason, we present a case of myositis ossificans traumatica o f the sternocleidomastoid muscle in a patient with squamous cell carcinoma o f the larynx, which was suspected clinically to be a lymph-node metastasis.

Case report The patient, then a 65-year-old man, presented originally in 1987 with a T2 squamous cell carcinoma of the lateral border of the left tongue. This was resected in continuity with a suprahyoid dissection of the left neck and reconstructed with a fasciocutaneous radial forearm free flap. He remained well with no evidence of local or regional disease until September 1993, when" he complained of hoarseness of 2 months' duration. He underwent examination under anaesthesia. Direct laryngoscopy was technically difficult, and it revealed an extensive lesion involving the left vocal cord. The neck was assessed as negative for metastatic disease. Histologie examination of the laryngeal biopsy showed a moderately well-differentiated squamous cell carcinoma. The case was discu.ssed at the joint head and neck oncology clinic. Radiotherapy was determined to be the best treatment for the patient. Four weeks later, and before radiotherapy

Key words: myositis ossificans traumatica; stemocleidomastoid. Accepted for publication 2 August 1994

had commenced, the patient re-presented at the maxillofacial surgical unit with a firm, fixed, 3×5 cm mass in the left neck, at the level of the jugulodigastrie nodes. Fine needle aspiration (FNA) was equivocal because it revealed "moderate numbers of atypical cells, not characteristic of squamous carcinoma, occasionally resembling ganglion cells". A computerized tomography (CT) scan showed a mass, with patchy enhancement, intimateIy associated with the upper third of the sternocleidomastoid muscle (Fig. 1). Extracapsular spread from a metastatic lymph node was proposed as the most likely diagnosis. Consequently, the treatment plan ~zs changed, and the patient underwent a total laryngectomy in continuity with a radical dissection of the left neck.

Pathology The resection specimen was the result of a total laryngectomy in continuity with a radical dissection of the left neck. A hard mass,

Myositis ossificans traumatica

Fig. 1. Axial CT section showing irregularly shaped and scattered radiopacities within left sternocleidomastoid muscle (asterisk).

Fig. 2. Low-power photomicrograph showing proliferated fibrous tissue (F) and newly formed bone (B) and cartilage (C). Skeletal muscle fascicles (asterisks) are seen (HE, ×12.5).

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were present throughout the larynx and epiglottis. Metastatic carcinoma ',,,'asnot identified in any of the 33 lymph nodes. Discussion

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Fig. 3. High-po~er photomicrograph showing bizarre nucleolated osteoblast-like cells (arrowhead) lining cellular osteoid (HE ×50).

Fig. 4. Osteoclast-like giant ceils (arrowheads) associated with bone and set in cellular fibrous stroma (HE ×50).

approximately 3.0 cm, in size, was palpated at the superior cervical level. On gross dissection, the mass was found to be within the sternocleidomastoid muscle. It consisted of a multilobular, coralline structure. Gross examination of the laryngectomy specimen revealed an extensive, exophytic tumour involving the supraglottis, the vocal cords, and the left subglottis. A total of 33 lymph nodes were recovered from tlae neck dissection. Histologic examination of the sternocleidomastoid showed irregularly shaped trabeculae of osteoid, poorly mineralized woven bone, and hyaline cartilage, extending be-

twccn and within bundles of muscle fibres (Fig. 2). The trabcculae were cuffed by mononuclear, osteoblast-like cells, with distinct nucleoli (Fig. 3), and multinuclear, osteoclast-like cells (Fig. 4). Cellular atypia and mitotic figures were inconspicuous. A diagnosis of myositis ossifieans traumatica was made. Histologic assessment of the larynx confirmed the original biopsy, diagnosis of squamous cell carcinoma, with extensive replacement of the submucosa of the supraglottie vestibule and the subglottic space. In addition, multiple foci of severe dysplasia

Myositis ossificans traumatica (myositis ossificans eircumscripta; extraosseous localized nonneoplastic bone and cartilage formation) is a localized, self-limiting, ossifying process of skeletal muscle, or, more rarely, tendons, fasciae, periosteum, and subcutaneous fat x. The exact pathogenesis is uncertain, but most cases follow mechanical injury, either repeated minor trauma or an isolated acute trauma. It is likely that intramuscular haemorrhage is followed by exuberant proliferation of vascular granulation tissue, and its maturation to fibroblastic tissue with progressive formation of bone and cartilage. The exact environmental conditions underlying the ossification process have not been elucidated. Moreover, the precise origin of the osteoid-producing ceils is uncertain, but fibroblasts or primitive mesenchymal cells are the most likely sources 3. Myositis ossificans traumatica should not be confused with myositis ossificans progressiva (fibrodysplasia ossificans progressiva), a rare disease of probably genetic origin which presents in early childhood with ossification of multiple muscle groups 4. Myositis ossificans traumatica affects the limbs most frequently, most reported cases involving the quadriceps and brachialis muscles 6. To our knowledge, there are no reports of myositis ossificans traumatica of the sternocleidomastoid muscle in the recent literature. In the present case, it is likely that the causative trauma was iatrogenic in origin, resulting from the direct laryngoscopy and biopsy procedure. The maturity of the lesion, as judged histologically, would support this hypothesis. Given the clinical history, biopsy result, and equivocal F N A and radiologic findings, the preoperative diagnosis of metastatic carcinoma within a cervical lymph node was reasonable. Histologically, there was no evidence of lymph-node tissue, and the mass was clearly within the confines of the sternocleidomastoid muscle. The main histologic differential diagnosis that was considered was extraskeletal osteosarcoma. However, the architecture and orderly maturation, the abundance of well-formed bone and cartilage, and the lack of cellular atypia in the present

Myositis ossificans tra,tmatica lesion fa'voured the diagnosis of the reactive condition of myositis ossificans, rather than the neoplastic condition. Furthermore, the distinct nucleoli present in the osteoblast-like cells (Fig. 3) may account for the description of ganglion-like cells in the F N A specimen.

Acknowledgment. We acknowledge Mr E. D. Vaughan for permission to report this case.

References l. ACKERMAN LV. Extra-osseous localized non-neoplastic bone and cartilage formation (so-called myositis ossificans). Clinical and pathological confusion with ma-

lignant neoplasms. J Bone Joint Surg 1958: 40A: 279-98. 2. BEARIISOH, BARBERKW. The value of radical dissection of structures of the neck in the management of carcinoma of the lip, mouth and larynx. Arch Surg 1962: 85: 49-54. 3. CIIALMERSJ, GRAY DH, RUSII J. Observations on the induction of bone in soft tissues. J Bone Joint Surg 1975: 57B: 3644. 4. CRAMER SF~ RUEIIL A, MANDLE MA. Fibrodysplasia ossificans progressiva. A distinctive bone-forming lesion of the soft tissue. Cancer 1981: 48: 1016-22. 5. CRISS.~IANJD, GLUCK.~IANJ, Wm'rELEYJ, QUENELLE D. Squamous cell carcinoma of the floor of mouth. Head Neck Surg 1980: 3: 2-7.

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6. ENZINGER FM, WEISS S~,V. Osseous tumors and tumorlike lesions of soft tissue. In: ENZINGER FM, WEXSSSW, eds. Soft tissue tumors. St Louis, MO: CV Mosb); 1988: 882-905. 7. ttE.NKJM, LANGDONJD. Management of the regional lymph nodes. In: HENK JM, LANGDON JO, eds.: Malignant tumours of the oral cavity. London: Edward Arnold, 1985: 186--203.

Address:

Julia A. IVoolgar, PhD, MRCPath Oral Pathology Laboratory UniversiO" of Liverpool Dental tlospital Pembroke Place Liverpool L3 5PS UK