Abstract and Introduction
Germinomas are gonadal neoplasms that rarely occur extragonadally in the midline structures of the human body. Newly diagnosed adult cases of pineal gland germinomas are very rare since most of the cases are diagnosed in the mid teens. The estimated incidence of this tumor in western countries is between 0.4–3.4%. Typically, this tumor is diagnosed by its characteristic radiological appearance alone, supported by tumor marker(s) or by stereotactic biopsy of the tumor. We are reporting a very unique case of pineal germinoma diagnosed in an adult at our institute by cerebrospinal fluid cytology with literature review. We analyzed case reports, literature reviews, and therapy and diagnostic articles about pineal germinoma in the English literature from 1983 to 2009 through the national library of medicine, Pubmed, and OVID search engines. We used key words "pineal germinoma," "pineal gland tumor," "CNS germinoma," and "extragonodal germinomas" to search for our articles.
Germ cell tumors (GCT) are classified into germinomas or nongerminomatous tumors (teratoma, embryonal carcinoma, endodermal sinus tumor, and choriocarcinoma) and their mixed types based on the histology. All the GCTs are malignant except for mature teratomas. Germinomas are the most common GCTs and account for 41–50% of all GCTs. These tumors are gonadal neoplasms but sometimes occur extragonadally in the midline structures of retroperitoneum and the mediastinum. Extragonadal GCTs account for only 2–3% of all GCTs. The central nervous system (CNS) is the most common site of involvement of extragonadal GCT.
Among the intracranial tumors, the GCTs are rare and account for 0.3 to 3.4% of all tumors. The GCTs maintain their affinity for the midline even within the CNS. Midline structures like the pineal gland are most commonly involved and account for 33–63% of all intracranial GCTs, followed by the suprasellar compartment.[2,3] Multiple midline or multicentric germinoma are terms that denote the involvement of both the above-mentioned sites by the GCT, and it occurs in 2% to 13% of reported cases of intracranial germinomas.[4–6] Other midline CNS structures that are affected are the thalamus and the basal ganglia.
The incidence of pineal germinoma varies from 0.4 to 3.4% in the West, whilst in Japan it is 5 to 8 times more frequent.[7,8] They are commonly diagnosed in the first and second decade of life with a median age of diagnoses being 10–12 years of age.[8,9] Pineal germinomas are mostly dealt with in pediatric neuro-oncology, and the neuroendocrine changes that occur around this time of life are thought to be the risk factor for their development. However, it may be seen rarely in adults.
Case reports have revealed a higher frequency of pineal germinomas in men as compared to women. The ratio of the incidence rate in men as compared to women is between 5:1 to 22:1.[1,3,10] This is probably due to chromosomal variations or variations in sex hormones and receptors between the genders. The embryologic theory of Sano postulates that the anterior neuropore closes earlier in males causing the enfolded embryonic cells to lie at the level of the superficial part of the neural tube that eventually forms the pineal gland.[11,3] Pineal germinomas are fascinating and rare, and are seldom reported in the literature. We present a case of pineal germinoma that was managed at our institution and have reviewed the available literature on this tumor.
South Med J. 2010;103(10):1031-1037. © 2010 Lippincott Williams & Wilkins
Cite this: Pineal Germinoma - Medscape - Oct 01, 2010.