Dr. Pepe’s Diploma Casebook: Case 6 – SOLVED!

Dear friends,

This week I want to show you a neuro/skeletal case, relating to a 25-year-old male with a 3-month history of sciatica.

Fig. 1

Fig. 2

Fig. 3

Most likely diagnosis:

1. Schwannoma
2. Perineural cyst
3. Sacrococcygeal teratoma
4. None of the above

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11 Responses to : Dr. Pepe’s Diploma Casebook: Case 6 – SOLVED!

  1. vishal kalia says:

    Pre and post contrast T1W, and T2W MR images with axial CT images showing a well defined focal lesion in the sacrum on right side at the level of SI vertebrae. The lesion is hypointense on T1W images and heterogenously hyperintense on T2W images with target appearance on T2(signal not parallel to CSF-rules out perineural cyst)). No evidence of any hyperintense T2 signal suggesting fatty component or hemorrhage is seen in it. No calcification is seen ruling out teratoma. The lesion is showing heterogenous enhancement on post contrast images. There is remodelling with expansion of the right ventral sacral foramen and the lesion is seen to extend into the presaral space on right side with dumbell appearance in saggital images.In axial T1W MR images the 1st sacral nerve root appears medial to the lesion.The diagnosis will be nerve sheath tumor(it is not possible to differentiate exactly between neurofobroma and schwannoma but the feature favouring schwannoma are -heterogenous enhacement and eccenteric S1 nerve root).

  2. Dr Hesham says:


  3. ardeshir says:


  4. Genchi Bari Italia says:

    Tumore benigno ,intradurale- extramidollare(TIEM).Ipointenso in T1;Iperintenso in T2;con impregnazione intensa in T1.Margini regolari con dislocazione della cauda equina. Diagnosi :Schawannoma.

  5. Xose says:

    I reckon it is a dumbell-shaped mass. There are some nonenhancing, as well as hypointense on T2-weighted images, areas. Why not neurofibroma?

  6. Albert says:

    I would also say nerve sheath tumor (schwannoma).

    • Albert says:

      I would consider in my differential for sacral mass: chordoma (destructive, with calcifications and very very hyperintense on T2 images), GCT (typically hypo on T2 and hypervascular, would not expect such sclerotic borders), teratoma (loof for fat hyper on t1), ABC (pseudo agressive lytic lesion with classical blood levels), osteoblastoma (lytic with or without sclerotic nidus and with solid nonagressive periosteal reaction), mets and plasmacytoma-mieloma (agressive and much more freq in older patients) and a small cell tumor like Ewing- PNET (much more heterogeneous and would expect more agressive appearance). My first option as I said would be by far the Nerve Sheath Tumor (schwannoma).

  7. Dr. F says:

    Classical dumbell shaped mass exiting the neural foramen. Neurofibroma. Less likely schwanoma. I would discuss further management with the primary physician. To differentiate the two, I would like to perfom MRI guided core biopsy. This will save the patient from Ct induced radiation. Other option would be to have complete surgical resection and send the specimen for histopathology.

  8. Kelvin says:

    Nerve sheath tumour.

    Dumbbell shaped, widening the neural foramen, and the other reasons mentioned by colleagues.

  9. Ricardo Macareno says:

    The findings are consistent with Schwannoma. (Complicated perineural cysts are extremely rare)

  10. Dr. Pepe says:

    Again, you are offering excellent discussions of the case. Imagine you have already obtained the Diploma. If not, you will not have any problems passing the examination.

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