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Right L4 nerve root mass

Dr. Rafael Medina Flores

University of Pittsburgh Medical Center
Presbyterian Ho spital

United States
Discussion in:
 Clinical Information
The patient is a 46-year-old female with a recent history of severe right leg pain with right leg weakness in the L4 nerve distribution. The patient was in her usual state of excellent health before presenting with the referred symptoms. A spine MRI showed a large homogeneously enhancing, intra and extradural mass arising from the right L4 nerve root. The mass caused expansion of the intervertebral foramen.

An L4 bilateral decompressive laminectomy was performed. The lamina of L4 was exposed through a 3-cm lower lumbar midline incision. The posterior spinous process of L4 was removed, as were the laminae. A swollen hemorrhagic tumor involving the right L4 nerve root was exposed and debulked. An intraoperative consultation was requested.

Imagen de Right L4 nerve root mass.
MRI showing a hyperintense extraspinal mass that grows through the intervertebral foramen.
Imagen de Right L4 nerve root mass.
Intraoperative smear,HE.
Imagen de Right L4 nerve root mass.
Frozen Section, HE.
Imagen de Right L4 nerve root mass.
Permanent section, HE.
Imagen de Right L4 nerve root mass.
Permanent section,HE.
Imagen de Right L4 nerve root mass.
Resultado da IHQ.


The 4/22/02 6:40, Bayardo Flores say:

En mi opinión se trata de un Schwannoma Melanótico Psammomatoso, aunque desconozco si la paciente es portadora de un síndrome de Carney, del cual esta lesión puede formar parte.




The 4/22/02 13:17, Gustavo Sales Barbosa say:

Também acho que se trate de um Schwannoma Melanocítico Psamomatoso. Geralmente é uma lesão benigna. Uma pequena quantidade pode metastizar, embora não se têm critérios bem definidos isoladamente para tal comportamento. Tumores clinicamente malignos geralmente apresentam núcleos grandes e vesiculosos com escassa cromatina;atividade mitótica elevada , algumas atípicas e extensas areas de necrose.

Um abraço



The 4/22/02 19:08, Juan María Loizaga, Sevilla, España say:

También pienso que sea un Schwanoma melanótico psamomatoso, pero convendría hacer el diagnóstico diferencial con el meningioma fusocelular que también puede tener melanina. Para ello una proteína S-100 sería necesario y también el EMA qque sría negativo en el Schwnoma aunque en la forma fusocelular del meningioma es positivo sólo en un bajo número de casos, pero entre ambos creo se podría llegar a un diagnóstico de seguridad. La posibilidad de un glioma es lejana pero la PGFA no vendría mal.


The 4/22/02 19:24, Darci Cardoso- Catanduva say:

Também concordo com o diagnóstico de Schwanoma melanótico psamomatoso. Belo caso!


The 4/23/02 1:13, Marlene Uribe say:

Favorezco un tumor neural de tipo schwannoma. En las fotografias no puedo distinguir si el pigmento es melanima o son macrofagos cargados de hemosiderina, puesto que el autor describio el tumor macroscopicamente como hemorragico. De ser melanina sería entonces un schwannoma melanotico. Gracias por compartir este inusual caso.Saludos


The 4/24/02 5:31, Javier Ortiz say:

lo mismo que otros compañeros pienso que puede tratarse de un schwannoma melanotico psamomatoso.¿se trata de un s.de Carney?


The 4/25/02 17:35, Romualdo Correia Lins Filho say:

Estimado Dr. Rafael Medina

Como todos os colegas que me precederam, também acho que se trate de um schwannoma melanótico psamomatoso. O surgimento de uma raiz nervosa, o envolvimento dos espaços intra e extradural e a expansão do forame intervertebral são

aspectos de grande importância para se afastar outras possibilidades, em especial um meningioma.


Romualdo Correia Lins Filho

Post a comment
Psammomatous Melanotic Schwannoma. (PMS) .
 Author Comment
Dear all,
Thanks again for your thoughtful comments, you were all "right on the money" from the beginning. This is indeed a Psammomatous Melanotic Schwannoma. (PMS)

PMS was first described by Carney as a "distinctive, heritable tumor associated with cardiac myxoma and Cushing's syndrome". PMS commonly arise in spinal nerve roots, GI tract and bones. Grossly, they are described as "dumbbell shaped", unencapsulated, sometimes cystic tumors with a distinct black, blue-brown pigmentation. Microscopically, these neoplasms are composed of spindle and epithelioid cells arranged in fascicles or whorls. Melanin pigment is abundant in tumor cells, and melanophages, Psammoma bodies are present, and occasionally one might see focal microvesicular change with some resemblance to fat.

Fifty percent of PMS are associated with Carney's complex which is a multiple endocrine neoplasia (MEN) syndrome that affects the adrenal cortex, pituitary, thyroid glands, and gonads. The complex is also associated with skin and mucosal pigmentation abnormalities and neoplasms of myxoid, neuroectodermal and mesenchymal origin. (Carney's complex should not to be confused with Carney's triad: multiple paragangliomas, gastric stromal sarcoma, and pulmonary chondroma or the recently described syndrome of familial paraganglioma and gastric stromal sarcoma).

On MRI most peripheral nerve sheath tumors are hypointense on T1 and hyperintense on T2 weighed images, this is the opposite of PMS and other melanin containing tumors that are distinctly hyperintense on T1 and hypointense on T2 weighed images. The high T1 signal in melanotic tumors is attributed to the abundance of paramagnetic free radicals in melanin.

The histologic differential diagnosis includes: conventional schwannoma, pigmented neurofibroma, melanocytoma, metastatic melanoma and clear cell sarcoma of soft tissues (See AFIP fascicle of peripheral nerve tumors). Immunohistochemical studies are helpful, PMS are strongly immunoreactivity for HMB-45 (Figure 6. Red Chromogen), S-100 protein (Figure 7. Red chromogen), Vimentin, Laminin, type IV collagen and CD56 (Figure 8). Ultrastructurally, melanosomes and basal lamina formation are readily seen.

Unlike conventional schwannomas, PMS may follow a malignant course after a local recurrence. Although no definite histologic criteria for malignancy exist at this time, the presence of large vesicular nuclei, prominent nucleoli, necrosis and mitoses should raise concern for recurrence and or metastatic potential.

Recently, Stratakis et al have put forward a set of diagnostic criteria for Carney's complex (Stratakis CA, Kirschner LS, Carney JA. Clinical and molecular features of the Carney complex: diagnostic criteria and recommendations for patient evaluation J Clin Endocrinol Metab 2001 Sep;86(9):4041-6.). Be aware that even without all of the other manifestations of Carney's complex, if the patient has a PMS and an inactivating mutation of the PRKR1A gene on chromosome 17, he or she should is best classified as having Carney's Complex.

The initial workup of patients with PMS, includes an echocardiogram (rule out cardiac myxomas), urinary free cortisol levels, serum IGF-I levels, male patients should have testicular USG, thyroid USG at initial evaluation, Dexamethasone-stimulation test, etc.

By the way this patient does not have any of the clinical manifestations of Carney's complex, genetic studies to rule out an inactivating mutation of the PRKAR1A gene are pending.

Best wishes,

Rafael Medina-Flores, MD
Neuropathology Fellow
UPMC Health System
Presbyterian Hospital
Pittsburgh, PA, USA.
1: Kirschner LS, Sandrini F, Monbo J, Lin JP, Carney JA, Stratakis CA. Genetic heterogeneity and spectrum of mutations of the PRKAR1A gene in patients with the carney complex. Hum Mol Genet. 2000 Dec 12;9(20):3037-3046.

2: Cummings TJ, Liu K, Jordan LK 3rd, Dodd LG. Fine-needle aspiration diagnosis of psammomatous melanotic schwannoma. Diagn Cytopathol. 2000 Jul;23(1):55-58.

3: Watson JC, Stratakis CA, Bryant-Greenwood PK, Koch CA, Kirschner LS, Nguyen T, Carney JA, Oldfield EH. Neurosurgical implications of Carney complex. J Neurosurg. 2000 Mar;92(3):413-418. Review.

4: Hollinger P, Godoy N, Sturzenegger M. Magnetic resonance imaging findings in isolated spinal psammomatous melanotic schwannoma. J Neurol. 1999 Nov;246(11):1100-1102.

5: Leger F, Vital C, Rivel J, Benjelloun B, San Galli F, Guerin J. Psammomatous melanotic schwannoma of a spinal nerve root. Relationship with the Carney complex. Pathol Res Pract. 1996 Nov;192(11):1142-1146

6: Carney JA. The Carney complex (myxomas, spotty pigmentation, endocrine overactivity, and schwannomas). Dermatol Clin. 1995 Jan;13(1):19-26.

7: Carney JA. Psammomatous melanotic schwannoma. A distinctive, heritable tumor with special associations, including cardiac myxoma and the Cushing syndrome. Am J Surg Pathol. 1990 Mar;14(3):206-222.

8: Carney JA, Stratakis CA. Familial paraganglioma and gastric stromal sarcoma: a new syndrome distinct from the Carney triad. Am J Med Genet. 2002 Mar 1;108(2):132-139.

9: Stratakis CA, Kirschner LS, Carney JA. Clinical and molecular features of the Carney complex: diagnostic criteria and recommendations for patient evaluation. J Clin Endocrinol Metab. 2001 Sep;86(9):4041-4046.

10: Carney JA, Boccon-Gibod L, Jarka DE, Tanaka Y, Swee RG, Unni KK, Stratakis CA. Osteochondromyxoma of bone: a congenital tumor associated with lentigines and other unusual disorders. Am J Surg Pathol. 2001 Feb;25(2):164-176.

11: Kirschner LS, Carney JA, Pack SD, Taymans SE, Giatzakis C, Cho YS, Cho-Chung YS, Stratakis CA. Mutations of the gene encoding the protein kinase A type I-alpha regulatory subunit in patients with the Carney complex. Nat Genet. 2000 Sep;26(1):89-92.
NOTE: This is a professional medical forum which object is not offer medical or helth consultation. Messages sent for this advices will not attend. Scientific information offered is supported by references and bibliography and authors are responsibles of their veracity. Participation is free.

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