Pineal embryonal carcinoma
Synonyms and keywords: Pineal embryonal cell carcinoma; Pineal gland tumor; Brain tumor

# Overview
Pineal embryonal carcinoma is a relatively rare malignant neoplasm and accounts for a small proportion of all intracranial germ cell tumors. It is an aggressive tumor and has a propensity to metastasize systemically. A component of embryonal carcinoma is often found in mixed germ-cell tumors, in which case it is usually the most aggressive component, and dictates prognosis. Pure pineal embryonal carcinoma tumors do not secrete -HCG or AFP. On microscopic histopathological analysis, pineal embryonal carcinoma is characterized by: Poorly differentiated, pleomorphic cells in cords, sheets, or papillary formation, indistinct cell borders, nucleoli, vesicular nuclei (clear, empty appearing nuclei) and necrosis. If left untreated, patients with pineal embryonal carcinoma may progress to develop seizures, obstructive hydrocephalus, and CSF metastasis. Common complications of pineal embryonal carcinoma include: Obstructive hydrocephalus, leptomeningeal spread, and systemic metastasis.  The clinical presentation of pineal embryonal carcinoma is mainly from the obstructive hydrocephalus secondary to compression of the tectum of the midbrain and obstruction of the aqueduct. Symptoms of pineal embryonal carcinoma include headaches, nausea, vomiting, seizures, hearing loss, sleepiness, and double vision. Compression of the superior colliculi can lead to a characteristic gaze palsy, known as Parinaud syndrome. Head CT and brain MRI may be diagnostic of pineal embryonal carcinoma. Biopsy is generally done to confirm the diagnosis of pineal embryonal carcinoma. The mainstay of therapy for pineal embryonal carcinoma is radiotherapy and/or chemotherapy. Sometimes, surgical resection may be done. CSF diversion, radiation, and stereotypical surgery are alternative treatment options based on the patient situation.

# Pathophysiology
- Pineal embryonal carcinoma is a relatively rare malignant neoplasm and accounts for a small proportion of all intracranial germ cell tumors.
- It is an aggressive tumor and has a propensity to metastasize systemically.
- A component of embryonal carcinoma is often found in mixed germ-cell tumors, in which case it is usually the most aggressive component, and dictates prognosis.
- Pure pineal embryonal carcinoma tumors do not secrete -HCG or AFP.
- On microscopic histopathological analysis, pineal embryonal carcinoma is characterized by:
Poorly differentiated, pleomorphic cells in cords, sheets, or papillary formation
Indistinct cell borders
Nucleoli - key feature
Vesicular nuclei (clear, empty appearing nuclei) - key feature
Necrosis - common
Mitoses - common
Variable architecture:
Solid (predominant in ~55% of cases)
Glandular (predominant in ~17% of cases)
Papillary (predominant in ~11% of cases)
Nested
Micropapillary
Anastomosing glandular
Sieve-like glandular
Pseudopapillary
Blastocyst-like
Embryoid bodies - ball of cells in surrounded by empty space on three sides
- Poorly differentiated, pleomorphic cells in cords, sheets, or papillary formation
- Indistinct cell borders
- Nucleoli - key feature
- Vesicular nuclei (clear, empty appearing nuclei) - key feature
- Necrosis - common
- Mitoses - common
- Variable architecture:
Solid (predominant in ~55% of cases)
Glandular (predominant in ~17% of cases)
Papillary (predominant in ~11% of cases)
Nested
Micropapillary
Anastomosing glandular
Sieve-like glandular
Pseudopapillary
Blastocyst-like
Embryoid bodies - ball of cells in surrounded by empty space on three sides
- Solid (predominant in ~55% of cases)
- Glandular (predominant in ~17% of cases)
- Papillary (predominant in ~11% of cases)
- Nested
- Micropapillary
- Anastomosing glandular
- Sieve-like glandular
- Pseudopapillary
- Blastocyst-like
- Embryoid bodies - ball of cells in surrounded by empty space on three sides
- Pineal embryonal carcinoma is demonstrated by positivity to tumor markers such as:
- OCT4
- CD30

# Differentiating Pineal Embryonal Carcinoma From Other Conditions
- Pineal embryonal carcinoma must be differentiated from:
- Pineocytoma
- Pineal parenchymal tumor with intermediate differentiation
- Papillary tumor of the pineal region
- Pineoblastoma
- Pineal germinoma
- Pineal choriocarcinoma
- Pineal yolk sac carcinoma (endodermal sinus tumor)
- Pineal teratoma
- Pineal cyst
- Astrocytoma of the pineal gland
- Meningioma near pineal gland
- Pineal metastasis
- Cavernoma in pineal region
- Aneurysm in pineal region  If left untreated, patients with pineal embryonal carcinoma may progress to develop seizures, obstructive hydrocephalus, and CSF metastasis.

# Natural History, Complications, and Prognosis
- Pineal embryonal carcinoma is a relatively rare malignant neoplasm and accounts for a small proportion of all intracranial germ cell tumors.
- It is an aggressive tumor and has a propensity to metastasize systemically.
- Common complications of pineal embryonal carcinoma include:
- Obstructive hydrocephalus
- Leptomeningeal spread
- Systemic metastasis

# Clinical Findings
- The clinical presentation of pineal embryonal carcinoma is mainly from the obstructive hydrocephalus secondary to compression of the tectum of the midbrain and obstruction of the aqueduct.
- Symptoms of pineal embryonal carcinoma include:
Headaches
Nausea and vomiting
Seizures
Hearing loss
Sleepiness and confusion
Double vision
- Headaches
- Nausea and vomiting
- Seizures
- Hearing loss
- Sleepiness and confusion
- Double vision
- Compression of the superior colliculi can lead to a characteristic gaze palsy, known as Parinaud syndrome.
- Head CT and brain MRI may be diagnostic of pineal embryonal carcinoma.
- Biopsy is generally done to confirm the diagnosis of pineal embryonal carcinoma.

# Treatment
The mainstay of therapy for pineal embryonal carcinoma is radiotherapy and/or chemotherapy. Sometimes, surgical resection may be done.