Clinical History
A 52-year-old lady initially presented with episodes of haemoptysis, weight loss and non-resolving chest X-ray changes despite a course of antibiotics. She subsequently developed generalised tonic clonic seizures, drop attacks and feelings of imbalance tending to veer to the left.
Imaging Findings
An initial chest X-ray showed progression from segmental consolidation to an opacity in the right mid zone.
CT chest showed a spiculated soft tissue mass predominantly within the right lung lower lobe with right hilar, precarinal and subcarinal lymphadenopathy. A low attenuation lesion was identified within segment 8 of the liver and an enlarged left adrenal. These findings suggested a primary bronchogenic carcinoma (CT staging T2b-N2-M1b) with liver and left adrenal gland metastasis.
After developing neurological symptoms, MRI brain showed a focal 10 millimetre right parietal lobe enhancing lesion with surrounding oedema and minimal effacement to the posterior right lateral ventricle. Further lesions were seen in the frontal lobe and right cerebellar hemisphere. A 15 millimetre enhancing rounded lesion was identified in the pineal gland causing obstructive hydrocephalus with third and lateral ventricle temporal horn dilatation. These appearances confirmed a metastatic pineal gland deposit with further multiple intracerebral metastases.
Discussion
The pineal gland is located in the dorsal aspect of the diencephalon. It secretes melatonin, a hormone which has antihypertensive, anticancer and anti-oxidant effects.
Primary pineal gland lesions are uncommon, accounting for less than 1% of all intracranial tumours in adults and 3–8 % in children [1]. Pineal gland metastasis as seen in our case is exceptionally rare partly due to little systematic post mortem study. There have been relatively few reports offering discussion of diagnosis and treatment modalities on this type of metastasis.
The lungs are the most common type of primary to metastasize, followed by breast and malignant melanoma and less frequently the kidneys and rectum [2]. Small cell carcinoma is the most commonly implicated histological type from the lung followed by squamous cell carcinoma and adenocarcinoma [2].
Usually asymptomatic but it can present with vertigo, headache or vertical gaze palsy.
Pineal involvement usually produces symptoms indirectly through compression of the sylvian aqueduct resulting in hydrocephalus [3].
Diagnosis was previously made by autopsy, but with MRI, detection of pineal masses have improved early detection of such lesions. High resolution MRI with gadolinium enhancement is excellent at defining tumour characteristics and its anatomic relationship with surrounding structures. Pineal lesions are typically hypointense to isointense on T1-weighted images, have increased signal on T2, and demonstrate homogenous enhancement after gadolinium administration. Stereotactic brain biopsy can be considered if tissue diagnosis is required [4].
The main goal of treatment is relief of neurological symptoms by decompression of hydrocephalus with VP shunting. But this is associated with an additional risk of peritoneal dissemination of malignancy and infection. Surgery by occipital trans-tentorial (OTT) approach and regional radiotherapy are more definitive treatments aimed at tumour control [5]. Our patient unfortunately remained too unwell to have any surgical intervention or radiotherapy. Survival depends on the aggressiveness of the primary tumour and the metastatic burden. However, it generally remains very poor with less than 1% 5-year survival rate [6].
Conclusion: Pineal gland metastasis has only ever been reported in a handful of cases. Within these, widespread distribution of metastasis has been noted with neurological symptoms developing later on. If a patient exhibits focal neurology, a metastasis should be considered as a cause when encountering a pineal gland lesion, especially in elderly patients with a known primary cancer.
Differential Diagnosis List
Primary lung cancer with pineal gland metastasis
Germ cell tumours - germinoma
teratoma
Pineal parenchymal tumour- Pineocytoma
Glioma
Final Diagnosis
Primary lung cancer with pineal gland metastasis
