Rare Pituitary Metastasis from Adenocarcinoma of Right Lung in ¹⁸F FDG PET/CT

Abstract

Lung cancer is the leading cause of cancer and cancer-related deaths, and India ranks the fourth highest country. Lung cancer is a highly aggressive malignancy with a tendency for rapid progression, making early detection and prompt treatment essential for improving patient outcomes. Lung cancer can spread locally into surrounding tissue as well as travel through lymphatics to other parts of the body, most often to bone, brain, liver, and adrenal glands. Metastasis to pituitary and pineal glands is extremely rare. The differential diagnosis for pituitary metastasis could be pituitary adenoma where lesion usually lies at the anterior aspect of pituitary fossa, whereas metastasis is seen at the posterior aspect. There is a paucity of published literature, with only a few cases reported of pituitary and pineal gland metastasis. Hence, to add to the literature, we present a case of pituitary metastasis in an older woman with lung cancer.

A 50-year-old female from a rural village in India presented with bilateral cervical swelling and cough for 4 months. On biopsy from the right supraclavicular lymph node, it showed metastatic adenocarcinoma from lung origin. She had no smoking history and was known hypertensive on medication for 4 years. Flurodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) done as initial workup [Figure 1], showed FDG avid primary right lung lesion with bilateral supraclavicular and mediastinal lymph nodes and liver and skeletal lesions. The patient was started on pembrolizumab (PDL-1 inhibitor) and chemotherapy comprising paclitaxel and carboplatin. FDG PET/CT done after 3 cycles of treatment [Figure 2] for response assessment, showed progressive disease along with brain metastasis to pituitary gland [Figure 3]. Further patient was advised magnetic resonance imaging (MRI) brain for confirmation, which showed multiple hyperintense brain lesions, including lesions at pituitary and additional pineal gland at T2W/fluid-attenuated inversion recovery (FLAIR) MRI imaging [Figure 4].

Figure 1.

Pretherapy max intensity projection image of flurodeoxyglucose (FDG)-positron emission tomography computed tomography (base of skull–thigh) scan shows FDG-avid right lung lesion with bilateral supraclavicular and mediastinal lymph nodes and liver and skeletal lesions

Figure 2.

Posttherapy max intensity projection image of flurodeoxyglucose (FDG)-positron emission tomography computed tomography (base of skull–thigh) scan shows frank increase in FDG avid lesions, denoting progressive disease

Figure 3.

(a and b) Sagittal sections computed tomography (CT) brain and fused positron emission tomography (PET)/CT shows soft tissue lesion at pituitary fossa with increased flurodeoxyglucose (FDG) uptake. (c and d) Axial sections CT brain and fused PET/CT show soft tissue lesion at pituitary fossa with increased FDG uptake

Figure 4.

Sagittal section of T2W/fluid-attenuated inversion recovery magnetic resonance imaging shows enhancing lesions at posterior part of pituitary gland (blue arrow) and pineal gland (green arrow)

Lung cancer is the leading cause of cancer and cancer-related deaths, and India ranks the fourth highest country.[1] Small cell lung cancer have shown maximum propensity to metastasize to the brain at the initial diagnosis compared to non small cell varieties.[2] However, pituitary metastasis is rare and shows poor signifies.[3] Pituitary adenoma, in which the lesion often occurs at the anterior aspect of the pituitary fossa while metastasis is observed at the posterior aspect, could be the differential diagnosis for pituitary metastasis.[4]

According to literature few cases of pituitary metastasis have been published.[5,6,7,8,9,10,11] and accounts for <1% of all intracranial metastasis.[9] A rare case of pineal gland metastases has been found from adenocarcinoma lung.[12] Biopsy is a method of diagnosis, but being intracranial difficult to perform and could be hazardous to the patient as well. Henceforth, imaging technique MRI as well as PET/CT can be used for detecting metastatic spread including at brain.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.