Male patient, 53 years old, had been showing
nasal obstruction for six months, otitis treated with inhaled antibiotics and
crenotherapy with no results. He also reported paresthesia on left hard palate.
He underwent rhinoscopy with optical fibres showing evidence of a neoformation
of the right nasal concha, basis right of the nasal cavity with subtotal
occlusion of the right posterior nasal aperture which impeded to see the
Eustachian tube orifice. A CT with contrast medium confirmed the presence of a
neoformation with partial involvement of the right pterygopalatine fossa,
delimited by a confining bone. As the neoformation was located, the patient
underwent an endoscopic transnasal surgical removal of the neoformation. Thehistological result initially showed the neoformation as a pleomorphic adenoma
of the right nasal cavity. After a revision of the slides in another centre a
phosphaturic mesenchymal tumour was diagnosed, due to the histological
polymorphism characterized by hyalinization with microcystic spaces and a
prevalence of chondroid and myxochondroid pattern. Later, the patient underwent
a revision of the surgery with enlargement of the surgical margins and with a
completely negative histological result for the disease. Moreover the
concentration of calcium, phosphatemia and phosphaturia excluded Tumour-Induced
Osteomalacia (TIO). Today, after 8 months since the second surgery, the patient
appears to be free from the disease.
ETM PMTs are extremely rare. The diagnose is
usually late due to the presence of osteomalacia or to symptoms linked to a
local invasion. Patients affected by paraneoplastic syndrome can show
nonspecific bone pain, muscular weakness and pathological fractures. PMT
doesn’t show to have any link with sex and emerges to affect a very ample range
of patients, from the age of 3 to 73. 95% of PMTs were observed in bones and
only 5% in craniofacial districts. Among these about 50% of tumours were found
in the sinonasal tract. In our revision it was observed that 20 cases of PMT
reported in literature involve the sinonasal tract, while the rest of them
involve other ETM tracts, as mandible, mouth, pharynx, larynx, thyroid and
temporal bone. From a histological point of view PMT is characterized by
spindle-shaped or stellar cells in a myxochondroid or myxoid matrix with
calcification. Osteocytes in PMT are responsible for osteomalacia through the
production of Fibroblast Grow Factor 23 (FGF23), which inhibits the transport
of the sodium phosphate renal tubules leading to a phosphaturia and a consequent
bone demineralization. PMT is mostly suspected when a not familial
hypophosphatemia is present. Diagnostic workup must take into consideration the
patient’s history, an objective systemic exam and a search for localizations in
arms and legs and ETM. An otorhinolaryngologist who finds himself in front of a
histological PMT must investigate a possible osteomalacia, as most cases see
the presence of a paraneoplastic syndrome, and exclude the involvement of the bones.
In the series displayed in chart 1 it is possible to observe that only 6
patients didn’t present TIO. In an extensive revision carried out by Folpe et
al. on 109 mesenchymal tumours on the extremities, only 3 cases didn’t present
TIO. The first line treatment is surgical resection with ample margins, which
leads to a normalization of phosphatemia and phosphaturia with an improvement
of the mineralization of bones. The persistence of metabolic alterations after
surgical resection is predictive of an incomplete surgical resection or a
relapse. Surgery appears to be the best choice also for the rare malignant
manifestations of PMT, while adjuvant chemotherapeutic treatments haven’t been
established, yet, due to the small amount of cases.
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