Pineal germinoma

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Sujit Routray, M.D. [2]

Synonyms and Keywords: Pineal gland germinoma; Pineal germinomas; Germinoma of the pineal gland; Pineal dysgerminoma; Pineal dysgerminomas; Pineal gland tumor; Brain tumor

Overview

Pineal germinoma is the most common tumor of the pineal gland accounting for 50% of all tumors and the majority (80%) of intracranial germ cell tumors.[1] Pineal germinoma is a type of germ cell tumor. It refers to a tumor in the pineal gland that has a histology identical to two other tumors: dysgerminoma in the ovary and seminoma in the testis.[2]

Pathophysiology

Pathogenesis

  • Pineal germinoma is a malignant neoplasm of the germinal tissue of the pineal region.[2]
  • Germinomas are thought to originate from an error of development, when certain primordial germ cells fail to migrate properly. Germinomas lack histologic differentiation, whereas nongerminomatous germ cell tumors display a variety of differentiation. Like other germ cell tumors, germinomas can undergo malignant transformation.[3]

Associated Pathology

Gross Pathology

  • On gross pathology, pineal germinoma is characterized by a mass whose external surface is smooth and bosselated (knobby) and the interior is soft, fleshy, and either cream-coloured, gray, pink, or tan.[5]

Microscopic Pathology

  • On histopathological analysis, pineal germinoma is characterized by uniform large, round cells with vesicular nuclei and clear or finely granular cytoplasm that is eosinophilic. Typically, the stroma contains lymphocytes and approximately 20% of patients have sarcoid-like granulomas.[5]

Immunohistochemistry

Pineal germinoma is demonstrated by positivity to tumor markers such as:[6]

Differentiating Pineal Germinoma from other Diseases

Pineal germinoma must be differentiated from:[7][8]

Epidemiology and Demographics

Prevalence

Pineal germinoma is the most common tumor of the pineal gland, but accounts for less than 1% of all the intracranial tumors. Pineal germinoma accounts for 50% of all the pineal gland tumors and the majority (80%) of the intracranial germ cell tumors.[1][9]

Age

Pineal germinoma is a disease that tends to affect the children and young adult population.[10] Most patients are 20 years or younger at the time of diagnosis.

Gender

Males are more commonly affected with pineal germinoma than females. The male to female ratio is approximately 13 to 1.[10]

Natural History, Complications and Prognosis

Natural History

If left untreated, patients with pineal germinoma may progress to develop seizures, obstructive hydrocephalus, and CSF metastasis.[11]

Complications

Common complications of pineal germinoma include:[11][12]

Prognosis

  • Prognosis is generally excellent, and the 5-year survival rate of patients with pineal germinoma is approximately 90%.[13]
  • Multifocal or disseminated lesions are associated with poorer prognosis.[14]
  • Pineal germinoma usually presents with negative biological markers. The prognosis of patients with β-HCG secreting germinoma has been suggested to be worse than that of patients with pure germinoma.

History and Symptoms

History

  • When evaluating a patient for pineal germinoma, you should take a detailed history of the presenting symptom (onset, duration, and progression), other associated symptoms, and a thorough family and past medical history review.

Symptoms

Physical Examination

  • Compression of the superior colliculi can lead to a characteristic gaze palsy, known as Parinaud syndrome.[15]
  • Common physical examination findings of pineal germinoma include:[16]

HEENT

  • Bulging soft spots (fontanelles)
  • Eyes that are constantly looking down (sunsetting sign)
  • Deficiency in upward-gaze
  • Pupillary light-near dissociation (pupils respond to near stimuli but not light)
  • Convergence-retraction nystagmus
  • Papilledema

Neurological

CT

  • Head CT scan may be diagnostic of pineal germinoma.
  • Findings on CT scan suggestive of pineal germinoma include:[16][17]
  • Large midline mass in the pineal region
  • Hyperdense compared to normal brain
  • Vivid contrast enhancement
  • Calcification: usually representing "engulfed" pineal calcification

Gallery

MRI

  • Brain MRI may be diagnostic of pineal germinoma.
  • Features on MRI suggestive of pineal germinoma include:[16][19]
MRI component Findings

T1

  • Isointense to adjacent brain

T2

  • Isointense to adjacent brain

T1 with gadolinium contrast [T1 C+ (Gd)]

  • Vivid homogenous enhancement

Diffuse weighted imaging [DWI]

  • Restricted diffusion due to high cellularity

Gallery

Treatment

  • The mainstay of therapy for pineal germinoma is radiotherapy, since it is highly radiosensitive.[14]
  • In children, there is an attempt to reduce the toxicity of radiation therapy by the use of chemotherapy in combination with reduced dose radiation to decrease the volume of normal tissue irradiated by stereotactic radiotherapy.
  • The various chemotherapeutic agents that may be used for the treatment of pineal germinoma include:[14][21]
  • Patients with pineal germinoma will develop hydrocephalus in majority of the cases and they will require CSF diversion. Ventriculo-peritoneal (V-P) shunt placement is a viable option with low morbidity and mortality rate. However, shunt malfunction in this population is as high as 20%. In addition, tumor metastasis through a CSF shunt has been reported. Endoscopic third ventriculostomy (ETVC) is an alternative option, which also permits a biopsy of the tumor in the same procedure. Ahn et al. reported that the biopsy samples, obtained in the lateral ventricle or pineal region, were more favorable towards a successful diagnosis than those in the thalamus or tectal region. Neuroendoscopic biopsy procedures have been proven safe with low complication rates.[14]

References

  1. 1.0 1.1 Pineal germinoma. Dr Henry Knipe et al. Radiopaedia 2015. http://radiopaedia.org/articles/pineal-germinoma. Accessed on December 2, 2015
  2. 2.0 2.1 Classification of germinoma. Wikipedia 2015. https://en.wikipedia.org/wiki/Germinoma. Accessed on December 2, 2015
  3. Natural history of germinoma. Wikipedia 2015. https://en.wikipedia.org/wiki/Germinoma. Accessed on December 2, 2015
  4. Tan HW, Ty A, Goh SG, Wong MC, Hong A, Chuah KL (2004). "Pineal yolk sac tumour with a solid pattern: a case report in a Chinese adult man with Down's syndrome.". J Clin Pathol. 57 (8): 882–4. PMC 1770394Freely accessible. PMID 15280413. doi:10.1136/jcp.2004.016659. 
  5. 5.0 5.1 Histology of germinoma. Wikipedia 2015. https://en.wikipedia.org/wiki/Germinoma. Accessed on December 2, 2015
  6. Histology of pineal germinoma. Operative Neurosurgery 2015. http://operativeneurosurgery.com/doku.php?id=pineal_germinoma. Accessed on December 2, 2015
  7. Differential diagnoses of pineoblastoma. Dr Ayush Goel and Dr Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/pineoblastoma. Accessed on December 1, 2015
  8. DDx of pineoblastoma. Libre Pathology 2015. http://librepathology.org/wiki/index.php/Pineal_gland#Pineoblastoma. Accessed on December 1, 2015
  9. Epidemiology of pineal germinoma. Operative Neurosurgery 2015. http://operativeneurosurgery.com/doku.php?id=pineal_germinoma. Accessed on Dcember 2, 2015
  10. 10.0 10.1 Epidemiology of pineal germinoma. Dr Henry Knipe et al. Radiopaedia 2015. http://radiopaedia.org/articles/pineal-germinoma. Accessed on December 2, 2015
  11. 11.0 11.1 Clinical presentation of intracranial germ cell tumors. Dr Ayush Goel and Dr Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-germ-cell-tumours. Accessed on December 2, 2015
  12. Treatment and prognosis of pineal germinoma. Dr Henry Knipe et al. Radiopaedia 2015. http://radiopaedia.org/articles/pineal-germinoma. Accessed on December 2, 2015
  13. Prognosis of pineal germinoma. Operative Neurosurgery 2015. http://operativeneurosurgery.com/doku.php?id=pineal_germinoma#fn__22. Accessed on December 2, 2015
  14. 14.0 14.1 14.2 14.3 Alexiou, George A (2012). "Management of pineal region tumours in children". Journal of Solid Tumors. 2 (2). ISSN 1925-4075. doi:10.5430/jst.v2n2p15. 
  15. 15.0 15.1 Clinical presentation of pineal germinoma. Dr Henry Knipe et al. Radiopaedia 2015. http://radiopaedia.org/articles/pineal-germinoma. Accessed on December 2, 2015
  16. 16.0 16.1 16.2 16.3 Reddy MP, Saad AF, Doughty KE, Armstrong D, Melguizo-Gavilanes I, Cheek BS; et al. (2015). "Intracranial germinoma.". Proc (Bayl Univ Med Cent). 28 (1): 43–5. PMC 4264708Freely accessible. PMID 25552796. 
  17. CT radiographic features of intracranial germ cell tumors. Dr Ayush Goel and Dr Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-germ-cell-tumours. Accessed on December 2, 2015
  18. Image courtesy of Dr. Hani Al Salam. Radiopaedia (original file here). Creative Commons BY-SA-NC
  19. MRI radiographic features of intracranial germ cell tumors. Dr Ayush Goel and Dr Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-germ-cell-tumours. Accessed on December 2, 2015
  20. Image courtesy of Dr. Frank Gaillard. Radiopaedia (original file here). Creative Commons BY-SA-NC
  21. Treatment and prognosis of pineal germinoma. Wikipedia 2015. https://en.wikipedia.org/wiki/Germinoma. Accessed on December 3, 2015

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