Imaging of pediatric head and neck rhabdomyosarcomas with emphasis on magnetic resonance imaging and a review of the literature

Transorbital and endonasal resection of a rare orbital ectopic atypical meningioma

A female patient in her early 20s presented with increasing proptosis of her left eye over 2 months. She had no other signs of diplopia, pain or visual loss on initial presentation. Subsequent imaging of her orbits revealed a medial rectus tumour. A transorbital open biopsy of this tumour was non-diagnostic/inconclusive, hence a combined transorbital and endonasal resection of this tumour was performed. Histopathology of the resected tumour revealed an unusual inflammatory-rich spindle cell neoplasm, which was determined to be a primary orbital ectopic atypical meningioma. These tumours are exceedingly rare, with only case reports/series reported in the literature. Complete surgical resection with margins is the proposed treatment. The role of radiotherapy is still controversial. More studies are required to improve our knowledge of this condition.

Imaging findings in craniofacial childhood rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the commonest paediatric soft-tissue sarcoma constituting 3-5% of all malignancies in childhood. RMS has a predilection for the head and neck area and tumours in this location account for 40% of all childhood RMS cases. In this review we address the clinical and imaging presentations of craniofacial RMS, discuss the most appropriate imaging techniques, present characteristic imaging features and offer an overview of differential diagnostic considerations. Post-treatment changes will be briefly addressed.

Orbital rhabdomyosarcoma

BACKGROUND

Although rhabdomyosarcoma (RMS) is a rare tumor among the entire group of mesenchymal malignancies, it is a relatively common lesion and significant challenge for the ocular oncologist in terms of its diagnosis and management.

METHODS

A comprehensive literature search of articles published over the past 30 years in PubMed was conducted.

RESULTS

Orbital RMS usually presents as a space-occupying lesion in the orbit during the first decade and may mimic other neoplastic or inflammatory masses. The tumor has predilection for the superior nasal quadrant of the orbit. The clinical manifestations depend on the location of the tumor within the orbit and its rate of growth. The common histopathologic types are embryonal and alveolar varieties. CT and MR imaging are important in the evaluation of this tumor. Particular attention should be placed on the bone invasion and extension of the tumor into the intracranial cavity and paranasal sinuses. Treatment usually consists of a combination of chemotherapy and radiation therapy following excisional biopsy.

CONCLUSIONS

Survival of orbital RMS has improved due to advances in chemotherapy and radiotherapy. Posttreatment complications, including side effects of radiotherapy and secondary orbital malignancies, as well as visual dysfunction, occur more often and present new challenges due to improved long-term survival.

Neck masses in children

Infants and children with neck masses frequently present to the radiologist for further evaluation. The role of the radiologist is to differentiate between conditions using imaging modalities such as ultrasound with colour Doppler, CT and MRI. Where appropriate, the radiologist will also stage lesions for management purposes and aid in guiding aspiration or biopsy. This paper presents a pictorial review of paediatric neck masses and their imaging features. Particular emphasis is applied to the anatomical site of the mass to aid in differential diagnosis. It must be emphasised that the radiological findings should always be interpreted in conjunction with the patient's age, the clinical history and the findings on physical examination.

CT and MRI features of recurrent tumors and second primary neoplasms in pediatric patients with retinoblastoma

OBJECTIVE

The aim of our study was to describe the CT and MRI findings of recurrent tumors and second primary (malignant and benign) neoplasms in patients with retinoblastoma and to evaluate imaging features to assist in distinguishing them.

MATERIALS AND METHODS

Records of 445 pathologically confirmed retinoblastomas were retrospectively reviewed. Thirty-four patients with recurrent retinoblastomas and 15 patients with second primary neoplasms who underwent CT and MRI were evaluated by two radiologists with agreement by consensus.

RESULTS

Invasive patterns of recurrent tumors included type A, intraocular tumor (n = 13); type B, intraorbital tumor with spread into the optic nerve shown as enlargement and marked enhancement of the optic nerve on contrast-enhanced CT or MRI (n = 6); and type C, tumor extending to the lateral aspect of the orbit and invading the brain via the sphenoidal bone (n = 2). Thirty-eight percent of patients with recurrent tumors had distant metastases (n = 7) or leptomeningeal metastases (n = 6). Leptomeningeal metastases were found only in recurrent tumors. Second primary neoplasms included osteosarcoma (n = 5), rhabdomyosarcoma (n = 5), meningioma (n = 4), and other tumors (n = 3). A significant difference was seen between the patients' ages at the time of diagnosis of recurrent tumors and second primary neoplasms (p < 0.0001). Extraorbital tumors were found more frequently among second primary neoplasms than among recurrent tumors (p < 0.001).

CONCLUSION

Both recurrent tumors and second primary neoplasms in patients with retinoblastoma often show characteristic imaging features. The tumor distribution on CT and MRI may help in differentiating recurrent tumors and second primary neoplasms.

Median accessory digastric muscle: radiological and surgical correlation

A median accessory digastric muscle was revealed during a dissection of the submental region. The muscle was located between the anterior bellies of the digastrics, external to the mylohyoid and deep to the platysma. It appeared as a flat quadrilateral sheet. Its base arose from the front of the body of the hyoid bone near its upper border. Lower portion of the fibers, at the right base of the muscle, initially traveled perpendicular to the lower fibers of the right mylohyoid. The rest of the muscle had a median course, with the cranial end inserting into the mandible between the digastric fossae. The muscle elevated the hyoid bone and depressed the mandible when appropriate stress was applied. No other morphologic abnormalities were found in this region. Aberrant anterior bellies of the digastric muscles are uncommon and occur bilaterally or unilaterally. This observation of a median accessory digastric muscle has not previously been reported. Knowledge of this variant will help to avoid confusion with pathological conditions of the floor of the mouth and the submental region. It is relevant both for the interpretation of radiological images and during surgical procedures such as dissection of the anterior belly of the digastric for a malignant disease and graft positioning.

Rhabdomyosarcoma of the orbit. Evaluation with MR imaging and CT

Rhabdomyosarcoma is the most common primary orbital malignancy of childhood. It can present insidiously, mimicking other (benign) processes clinically and radiographically. CT and MR imaging are crucial in the diagnostic evaluation, treatment planning, and follow-up monitoring of the disease. Such imaging, especially when contrast is used, can accurately detect and state the extent of tumor involvement.

A follow-up of rhabdomyosarcoma of the infratemporal fossa region in adults based on the magnetic resonance imaging findings: case reports

Two adult patients with rhabdomyosarcoma of the infratemporal fossa region were evaluated by computed tomography and magnetic resonance imaging both before and after treatment. Successful treatment accompanied by reduction of the tumor mass as a result of chemotherapy was demonstrated in one patient. In the other patient a subsequent increase in the tumor mass was documented. Information on not only the size but also the internal architecture of the tumor may be useful when tumor response to therapy is being investigated. Magnetic resonance imaging is recommended as a method for outcomes evaluation in adult rhabdomyosarcoma cases.