Maxillary myxoid tumour

Case contributed by Dr David Preston

Presentation

A 23 year old male developed a swollen left cheek over a 4 week period. No history of trauma or recent infections.

Patient Data

Age: 23
Gender: Male
Modality: CT

There is an expansile soft tissue mass whose epicentre lies within the left maxillary sinus. There is associated bony thinning and destruction of the anterior and medial sinus walls. It demonstrates a discreet thin peripheral hyperdense rim which may represent calcification. There are also ill-defined hyperdense peripheral nodules. There is destruction of the adjacent superior alveolar process of the maxilla, with deviation of the premolars, but no impacted tooth identified.

The visualised brain defines normally. The foramina of the skull base are symmetrical. The left inferior orbital wall and boundaries of the pterygopalatine fossa are intact. The rest of the sinuses aerate normally. The masticator, carotid, parotid, pharyngeal mucosal and parapharyngeal spaces are symmetrical.

Conclusion

The expansile left maxillary sinus mass is concerning for a neoplastic process. Involvement of the superior alveolar process raises the possibility of a primary odentogenic mass such as ameloblastoma. A giant cell tumour is also a differential.

 

Modality: X-ray

Post op plain film.

The patient underwent a 17 hour operation involving both maxillofacial and ENT surgeons which included placement of a tracheostomy and reconstruction of the left maxilla using part of the patient's left fibula.

Histopathology: This specimen shows a tumour of low cellularity with bland spindle cells with slightly irregular oval or elongate nuclei and fine cytoplasmic processes in a background fine collagen strands separated by moderate quantities of myxoid ground substance. Scattered thin-walled capillary vessels are present. A small quantity of bone with probable new bone formation is present on the periphery. No odontogenic epithelium is seen. No mitosis, pleomorphism or necrosis is seen.

These appearances are of a myxoid tumour with low cellularity and scattered capillary vessels without pleomorphism (in this biopsy). My preferred diagnosis is myxoma/fibromyxoma although neither S100 positive cells nor patchy SMA/MSA positivity as found, are a feature of this neoplasm.

No chondroid areas are seen. Rhabdomyosarcoma (embryonal) is excluded with the negative desmin and myogenin. Solitary fibrous tumour is excluded with the negative CD34. Greater S100 positivity and more nuclear irregularity would be expected for a myxoid neurofibroma. No odontogenic epithelium is seen arguing against an odontogenic tumour.

Case Discussion

Neither radiology or pathology results were conclusive to an actual aetiology of the mass. What is clear is the destructive nature of the mass and need for resection to prevent further disfigurement.

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Case Information

rID: 23509
Case created: 20th Jun 2013
Last edited: 19th Nov 2015
System: Head & Neck
Inclusion in quiz mode: Included

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