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Case Reports

Indian Pediatrics 2004;41:839-842 

Fetal rhabdomyoma in a neonate

Ram Samujh
Ashish Dharmik
Kusum Joshi*
K.L.N. Rao

From the Departments of Pediatric Surgery and Histopathology*, Advanced Pediatric Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India 160 012.

Correspondence to: Dr. Ram Samujh, Postgraduate Institute of Medical Education and Research, Chandigarh, India 160 012. E-mail: rsamujh@yahoo.com

Manuscript received: June 19, 2003; Initial review completed: July 29, 2003; Revision accepted: January 20, 2004.


Rhabdomyoma is a rare benign tumour, majority arising from the cardiac muscle. Seventy to 90% of extra cardiac rhabdomyomas are found in the head and neck region, usually within the upper aero digestive tract. We report a case of rhabdomyoma of anterior neck in a neonate. Although rhabdomyomas of posterior neck have been reported, those reported in anterior triangle are infrequent. The lesion has not recurred one year after complete excision. There are no similar reports in Indian literature.

Kew words: Newborn, Rhabdomyoma.



The term rhabdomyoma was introduced by Zenker (1864) to indicate a benign tumour showing skeletal muscle cell with varying degree of differentiation and maturity(1). It was considered as a general diagnostic term for tumor as granular cell myoblastoma, alveolar soft tissue sarcoma, sarcoma botryoides, embryonal rhabdomyosarcoma, teratoma and mesenchymomas(2). Rhabdomyomas are currently defined as benign neoplasm of striated muscle tissue, consisting usually of polygonal frequently vacuolated glycogen containing cells with a fine granular deeply acidophilic cytoplasm resembling myofibril in cut section(3).

Most of the extracardiac rhabdomyomas in head and neck region in children are usually in posterior auricular region and pharynx. Anterior neck is an infrequent site. We report a case of extra cardiac rhabdomyoma of anterior neck in an infant.

Case Report

One-month-old female child presented with a swelling in the left submandibular region since birth. There was no redness or discharge and no feeding or respiratory difficulty noted. The general physical examination was unremarkable. The systemic examination did not reveal any abnormality. Local examination revealed a 8 × 6 cm swelling in left submandibular region, having bosselated surface, firm consistency, non tender, bimanually palpable and extending into the floor of mouth. The overlying skin was normal. There was no redness, scar or sinus or lymphadenopathy. X-ray soft tissue neck revealed a soft tissue mass with no calcification. Ultrasonography showed a solid lesion with heterogeneous and hyperechoic areas and no calcification. Fine needle aspiration cytology suggested a spindle cell tumor. NCCT head showed a septate cystic homogenous mass with extension superiorly behind the ramus of mandible, inferiorly till thoracic inlet, medially to the left para pharyngeal space displacing larynx and left carotid vessels and posteriorly reaching upto the border of sternocleidomastoid muscle. Local excision of tumor was done which revealed a well-defined solid tumor with cystic areas deep to omohyoid muscle in left sub mandibular region with no local infiltration. Histopathology of the resected tumor showed features of fetal rhabdomyoma. On histopathological examination, the tumor was composed of oval to spindle cells with vasicular nuclei. In most areas there was abundant intercellular myxoid material with few inflammatory cells (Fig.1). Few cellular areas with fascicular arrangement were seen. There was no pleomorphism or mitotic activity. Occasional strap cells with abundant eosinophilic cytoplasm were seen which showed cross striations by PTAH stain (Fig. 2), confirming skeletal muscle differentiation. The tumor cells were positive for desmin on immunohistochemistry.

Fig. 1. Photomicrograph of the tumor to show spindle cells in a loose Myxoid background (H. & E. × 140). Fig. 2. Photomicrograph to show cross striations (arrow) in the tumor cell (PTAH × 1360).


Rhabdomyomas are rare benign neoplasms of skeletal muscle cells found more frequently in the myocardium than in the striated muscles. The rare extra cardiac rhabdomyomas are true neoplasm and 70% occur in head and neck region. They are subdivided into adult, fetal and genital histological subtypes(4,5). The adult type of rhabdomyomas occur exclusively in the head and neck region. These are soft, coarsely lobulated tan to grey and well-circumscribed tumors ranging in size from 0.5 to 6.0 cm. Age of the patients range from 16 to 82 years (mean age 52 years). There is a marked male predominance of almost 5:1. A clonel balanced translocation has been found in Chromosome 15 & 17 in the head and neck rhabdomyoma(6). Majority of them require local excision with few local recurrence. Each recurrence is usually treated by local excision.

Fetal rhabdomyomas are benign tumors with skeletal muscle differentiation that have a propensity to occur in head and region. They are composed of elongated spindle shaped skeletal muscle elements in varying stages of differentiation. They are subdivided into two histological sub types "classic" immature histology and others with more prominent rhabdomyoblastic maturation "intermediate" histology(7). However, several tumors show overlapping features between classic and intermediate groups suggesting that these are more likely a single group with a spectrum of rhabdomyoblastic differentiation(7).

Fetal rhabdomyomas usually present as solitary mass within the soft tissue or the mucosal areas of head and neck. The may also present with hoarseness, dysphasia or respiratory distress. The most common sites are post auricular region, pre auricular region, or face, followed by nasopharynx and oral cavity. The differential diagnosis includes rhabdomyosarcomas (spindle cell variant) and benign hamartomatous lesions, such as neuro-muscular hamartomas and rhabdomyomatous measenchymal hamartomas of the skin(8,9). Distinction from spindle cell variant of rhabdomyosarcoma and other embryonal rhabdomyosarcomas may be difficult. Unlike rhabdomyosarcomas, which has infiltrative margins and invades normal tissues, fetal rhabdomyomas are well circumscribed and do not invade and destroy adjacent soft tissue. Histologically foetal rhabdomyomas rarely show areas of necrosis, and unlike rhabdomyosarcomas they lack hypercellularity, a "cambium layer" typical of botryoid rhabdomyosarmas, nuclear atypia, abnormally distributed chromatin and absent or low mitotic activity(10).

The subgroups of extra cardiac rhabdomyomas can further be characterized by immunocyto-chemical studies staining the myoglobin desmin vimentin muscle specific actin. Desmin is the most reliable marker for cells with skeletal or smooth muscle differentiation as it is present in both primitive and mature cells. Vimentin is present in primitive cells and myoglobin is present in mature cells(11).

The possibility of fetal rhabdomyoma should always be considered in differential diagnosis of a cervical swelling especially in a neonate.

Contributors: RS, AD reviewed literature and prepared the manuscript, KJ made the diagnosis on histopathology; KLNR managed the patient and will act as guarantor.

Funding: None.

Competing interests: None stated.




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