Oncogenic osteomalacia secondary to phosphaturic mesenchymal tumor

Case contributed by Harshad Arvind Vanjare , 14 Feb 2018
Diagnosis certain
Changed by Francis Deng, 22 May 2020

Updates to Study Attributes

Findings was changed:

Frontal chest radiograph showingshows diffuse osteopenia. Frontal radiograph of the lumbar spine shows diffuse osteopenia with variable decrease in vertebral body heights. Frontal radiograph of the pelvis and proximal femurs demonstrates coarse trabeculations involving bilateral femoral necks with the presence of looser zones.

Images Changes:

Image X-ray (Frontal) ( update )

Description was removed:
Frontal chest radiograph shows diffuse osteopenia.

Image X-ray (Frontal) ( update )

Description was removed:
Frontal radiograph of lumbar spine shows diffuse osteopenia with variable decrease in vertebral body heights

Image X-ray (Frontal) ( update )

Description was removed:
Frontal radiograph of pelvis and proximal femurs demonstrating coarse trabeculations involving bilateral femoral necks with presence of looser zones

Updates to Study Attributes

Findings was changed:

MRI brain shows a well defined lobulated, solid cystic-cystic mass in the left basifrontal region with extension into the olfactory groove. There is surrounding mass effect with midline shift to the right.

Specific findings:

  • T2: Well defined lobulated solid cystic mass in the left basifrontal region with extension into the olfactory groove. Surrounding mass effect with midline shift to right.
  • FLAIR: Cystic component did not show suppression on FLAIR.
  • T1: T1W hyperintense foci within the mass suggestive of internal haemorrhage or fat. 
  • T1 C+: The solid component of the mass demonstrating intense enhancement with extension into the left upper nasal cavity.
  • DWI/ADC: Negative for focal areas of hyperintensities to suggest diffusion restriction.
  • SWI: Multiple foci of blooming suggestive of internal hemorrhage.
Images Changes:

Image MRI (T2 fat sat) ( update )

Description was removed:
Well defined lobulated solid cystic mass in the left basifrontal region with extension into the olfactory groove. Surrounding mass effect with midline shift to right.

Image MRI (FLAIR) ( update )

Description was removed:
Cystic component did not show suppression on FLAIR.

Image MRI (T1) ( update )

Description was removed:
T1W hyperintense foci within the mass suggestive of internal haemorrhage.

Image MRI (T1 C+) ( update )

Description was removed:
The solid component of the mass demonstrating intense enhancement with extension into the left upper nasal cavity.

Image MRI (T1 C+) ( update )

Description was removed:
Extension into the left upper nasal cavity well seen.

Image MRI (DWI) ( update )

Description was removed:
Negative for focal areas of hyperintensities to suggest diffusion restriction.

Image MRI (ADC) ( update )

Description was removed:
Negative for focal areas of low signal to suggest diffusion restriction.

Image MRI (SWI) ( update )

Description was removed:
Multiple foci of blooming suggestive of internal hemorrhage.

Updates to Case Attributes

Body was changed:

At this stage the differentials considered were:

  1. haemangiopericytoma
  2. esthesioneuroblastoma
  3. phosphaturic mesenchymal tumour

The patient underwent left frontal craniotomy and total excision of the left anterior skull base mass. 

Histopathology: 

phosphaturic mesenchymal tumour, mixed connective tissue type

Discussion: 

Oncogenic osteomalaciaor tumour induced osteomalacia, is an acquired para-neoplastic syndrome.

Cases typically are diagnosed in 6th decade of life.

Tumours that can lead to this syndrome are classified histologically as:

  1. phosphaturic mesenchymal tumours with mixed connective tissue (70 -80%)
  2. osteoblastoma like tumours
  3. ossifying fibrous like tumours
  4. nonossifying fibrous like tumours

These tumours are often small in size and difficult to localize. The average time between the onset of symptoms and tumour localization is approximately 7 years.

These tumours often express somatostatin receptors. Therefore, scintigraphy using somatostatin analogue can be used for tumour localisation.

Cases can also have elevated serum Fibroblast Growth Factor 23 (FGF-23) levels which can be used for diagnosis or to assess disease progression. 

FDG-PET scan is increasingly been used for tumour localisation.

Treatment:

Tumour resection is the preferred treatment option.

Post-surgery, FGF-23 levels fall off drastically.

Serum phosphate and 1,25-dihydroxy vitamin D levels return to normal levels within days after tumour resection.

Long-term skeletal changes reverse within months.

  • -</ol><p>The patient underwent left frontal craniotomy and total excision of the left anterior skull base mass. </p><p><strong>Histopathology:</strong> </p><p>phosphaturic mesenchymal tumour, mixed connective tissue type</p><p> </p><p><strong>Discussion: </strong></p><p>Oncogenic osteomalacia<strong> </strong>or tumour induced osteomalacia, is an acquired para-neoplastic syndrome.</p><p>Cases typically are diagnosed in 6<sup>th</sup> decade of life.</p><p>Tumours that can lead to this syndrome are classified histologically as:</p><ol>
  • +</ol><p>The patient underwent left frontal craniotomy and total excision of the left anterior skull base mass. </p><p><strong>Histopathology:</strong> </p><p>phosphaturic mesenchymal tumour, mixed connective tissue type</p><p><strong>Discussion: </strong></p><p>Oncogenic osteomalacia<strong> </strong>or tumour induced osteomalacia, is an acquired para-neoplastic syndrome.</p><p>Cases typically are diagnosed in 6<sup>th</sup> decade of life.</p><p>Tumours that can lead to this syndrome are classified histologically as:</p><ol>
  • -</ol><p>These tumours are often small in size and difficult to localize. The average time between the onset of symptoms and tumour localization is approximately 7 years.</p><p>These tumours often express somatostatin receptors. Therefore, scintigraphy using somatostatin analogue can be used for tumour localisation.</p><p>Cases can also have elevated serum Fibroblast Growth Factor 23 (FGF-23) levels which can be used for diagnosis or to assess disease progression. </p><p>FDG-PET scan is increasingly been used for tumour localisation.</p><p>Treatment:</p><p>Tumour resection is the preferred treatment option.</p><p>Post-surgery FGF-23 levels fall off drastically.</p><p>Serum phosphate and 1,25-dihydroxy vitamin D levels return to normal levels within days after tumour resection.</p><p>Long-term skeletal changes reverse within months.</p><p> </p><p> </p>
  • +</ol><p>These tumours are often small in size and difficult to localize. The average time between the onset of symptoms and tumour localization is approximately 7 years.</p><p>These tumours often express somatostatin receptors. Therefore, scintigraphy using somatostatin analogue can be used for tumour localisation.</p><p>Cases can also have elevated serum Fibroblast Growth Factor 23 (FGF-23) levels which can be used for diagnosis or to assess disease progression. </p><p>FDG-PET scan is increasingly been used for tumour localisation.</p><p>Treatment:</p><p>Tumour resection is the preferred treatment option. Post-surgery, FGF-23 levels fall off drastically. Serum phosphate and 1,25-dihydroxy vitamin D levels return to normal levels within days after tumour resection. Long-term skeletal changes reverse within months.</p>

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