Metastatic melanoma to the pituitary gland

PET-CT in Clinical Adult Oncology-V. Head and Neck and Neuro Oncology

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT) has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate attenuation correction, so that radioactivity from deep or dense structures can be better visualized, but with head and neck malignancies it is critical to provide correlating detailed anatomic imaging. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging, and surveillance. This series of six review articles provides an overview of the value, applications, and imaging and interpretive strategies of PET-CT in the more common adult malignancies. The fifth report in this series provides a review of PET-CT imaging in head and neck and neuro oncology.

Abstract

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging, and longitudinal surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, and the potential pitfalls and nuances that characterize these applications. In addition, key tumor-specific clinical information and representative PET-CT images are provided to outline the role that PET-CT plays in the management of oncology patients. Hundreds of different types of tumors exist, both pediatric and adult. A discussion of the role of FDG PET for all of these is beyond the scope of this review. Rather, this series of articles focuses on the most common adult malignancies that may be encountered in clinical practice. It also focuses on FDA-approved and clinically available radiopharmaceuticals, rather than research tracers or those requiring a local cyclotron. The fifth review article in this series focuses on PET-CT imaging in head and neck tumors, as well as brain tumors. Common normal variants, key anatomic features, and benign mimics of these tumors are reviewed. The goal of this review article is to provide the imaging professional with guidance in the interpretation of PET-CT for the more common head and neck malignancies and neuro oncology, and to inform the referring providers so that they can have realistic expectations of the value and limitations of PET-CT for the specific type of tumor being addressed.

Melanoma metastasis to a nonfunctioning pituitary macroadenoma: illustrative case

BACKGROUND

Metastases to the central nervous system are often multiple in number and typically favor the gray-white matter junction. Collision tumors, defined as the coexistence of two morphologically different tumors, such as metastases to a known pituitary adenoma (PA), are exceedingly rare. Only a few reported cases of metastases to a PA exist in the literature.

OBSERVATIONS

The authors present the case of a 64-year-old man with a known history of stage IV metastatic melanoma who was found to have hypermetabolic activity in the sellar region on surveillance positron emission tomography. On laboratory evaluation, he had clear evidence of pituitary axis dysfunction without diabetes insipidus. Subsequent magnetic resonance imaging showed a 2.4-cm sellar mass with features of a pituitary macroadenoma and internal hemorrhage, although no clinical symptoms of apoplexy were noted. He underwent a transsphenoidal endoscopic endonasal approach for resection of the sellar lesion. Final pathology showed a collision tumor with melanoma cells intermixed with PA cells.

LESSONS

Histological analysis verified the rare presence of a collision tumor of a melanoma metastasis to a nonfunctional pituitary macroadenoma. Metastasis to a preexisting PA, although rare, should be considered in the differential diagnosis in patients with sellar lesions and a known cancer history.

Pituitary metastasis of malignant melanoma misdiagnosed as pituitary adenoma: A case report and systematic review of the literature

We report a case of malignant melanoma revealed by a metastasis to the pituitary gland. The tumor was misdiagnosed as a pituitary adenoma and aggressive transsphenoidal surgery was complicated by a cerebrospinal fluid fistula. Nine weeks later, the patient presented multiple leptomeningeal and brain metastases spreading from the sellar region. Regarding these observations, we conducted a systematic review of the literature in order to investigate clinicoradiological features that should lead clinicians to suspect pituitary metastasis and how it should impact the surgical management.

Solitary Metastatic Melanoma of the Pituitary Gland: Report of Two Cases and Literature Review

BACKGROUND

Pituitary melanoma metastases (PMMs) are extremely rare and only a few cases are reported in the literature. PMMs can grow rapidly and present local invasiveness, leading to acute onset of neurological symptoms such as headache, visual and oculomotion disorders or endocrinological signs such as diabetes insipidus and hypopituitarism, and can be life-threatening. For this reason, PMMs must be recognized and treated promptly.

CASE DESCRIPTION

The authors present 2 cases of PMMs managed at their institution, performing a review of the dedicated literature and analyzing current therapeutic strategies.

A Rare Case of Pituitary Melanoma Metastasis: A Dramatic and Prolonged Response to Dabrafenib-Trametinib Therapy

Introduction: Pituitary metastases (PM) are rare events and to date only very few cases of melanoma PM have been described in literature up to now. Case Presentation: We describe the clinical history of a 33-year-old male patient who underwent surgical excision of an inter-scapular melanoma in 2008. The subsequent follow-up was negative for ~10 years. In September 2018, due to the onset of a severe headache, the patient underwent a brain magnetic resonance imaging, which showed an expansive mass in the saddle and suprasellar region with a maximum diameter of 17 mm. Pituitary function tests and visual field were normal. Worsening of the headache and the appearance of a left eye ptosis led the patient to surgical removal of the lesion in October 2018. The histological examination unexpectedly showed metastasis of the melanoma. Post-operative hormonal assessment showed secondary hypothyroidism and hypoadrenalism, which were both promptly treated, and a mild hypogonadism. Three months after surgery, a sellar MRI showed a persistent, increased pituitary mass (3 cm of diameter); fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) detected an increased radiopharmaceutical uptake in the sellar region. Due to the persistence of the disease and the evidence of a BRAF V600E mutation, in February 2019, the patient underwent a combined treatment with dabrafenib (a BRAF inhibitor) and trametinib (mitogen-activated extracellular signal-regulate kinase inhibitor). Sellar MRI performed 6 months later showed no evidence of mass in the sellar region. The patient was in a good clinical condition and did not complain of headaches or other symptoms; there were no significant side-effects from the anticancer therapy. After 13 months of treatment, the patient showed no recurrence of the disease on morphological imaging. Anticancer therapy was confirmed, replacement therapies with hydrocortisone and levothyroxine continued and the pituitary-gonadal axis was restored. Conclusion: This is a very interesting case, both for the rarity of the pituitary melanoma metastasis and for the singular therapeutic course carried out by the patient. This is the first case of a pituitary melanoma metastasis with BRAF mutation, successfully treated with the combination of dabrafenib and trametinib after incomplete surgical removal.

Metastatic Spread to the Pituitary

The pituitary fossa is an uncommon site for metastatic tumor spread. Metastatic lesions to the sellar area derived mostly from breast, lung, renal, prostate, and colon cancers, and rarely from other solid and hematologic malignancies. Almost every cancer has been reported as a source of pituitary metastasis. Pituitary metastasis can involve both the anterior and posterior lobes, but the neuro-hypophysis is mainly involved. Clinical manifestations include diabetes insipidus, hypopituitarism, headache, visual disturbances, ophthalmoplegia, and also compression of adjacent structures by aggressive tumor masses. Metastatic spread to the pituitary from a distant primary malignancy is commonly associated with metastases to other tissues and poor prognosis, unless efficient systemic targeted medical treatment is available for the primary cancer (melanoma, lymphoma).

Prevalence of metastases within the hypothalamic-pituitary area in patients with brain metastases

Aim

To quantify the prevalence of brain metastases involving the hypothalamic-pituitary (HT-P) area.

Introduction

Cognitive impairment and fatigue are common side effects of whole brain irradiation (WBI) comprising the quality of life (QoL) for survivors. While the former is related to radiation-induced hippocampal injury, the latter could be secondary to hormonal disbalance as a consequence of radiation of the HT-P area. Thus, sparing both regions from higher irradiation doses could reduce these sequelae.

Methods

T1 contrast medium enhanced magnetic resonance imaging (MRI) scans of 865 patients with brain metastases (4,280 metastases) were reviewed. HT-P area was individually contoured with a margin of 5 mm in order to evaluate the prevalence of brain metastases in this region.

Results

Involvement of the hypothalamic region was found in 26 patients (involvement rate of 3% for patients and 1% for metastases), involvement of the pituitary gland in 9 patients (1% for patients and < 1% for metastases). Binary logistical regression analysis revealed the presence of > 10 brain metastases as the only factor associated with hypothalamic involvement while no distinct factor was associated with an involvement of the pituitary gland.

Conclusion

The low prevalence of metastases within the HT-P area in patients with brain metastases calls for further studies examining whether sparing of this region might improve patients QoL.

Twelve cases of pituitary metastasis: a case series and review of the literature

PURPOSE

The pituitary gland is an unusual site for metastatic spread, but as patients with metastatic malignancy are living longer, it may become more prevalent. Compression of important anatomy adjacent to the sella may produce disabling symptoms and endocrine derangement, leading to significant morbidity.

METHODS

An ambispective review of patient records between 2013 and 2017 from three neurosurgical centres was performed. After identifying cases, further investigation was performed to evaluate patient demographic, symptoms at presentation, radiological and histological findings, management, and outcome.

RESULTS

Our investigation identified 12 patients with pituitary metastasis. The average age of the cases was 63.4 years, with breast (n = 4) and lung (n = 4) being the most common primary cancers. In half the cases there was a history of metastatic disease, while in one-quarter of cases, pituitary symptoms were the first sign of malignancy. Adenohypophyseal dysfunction (83%), diabetes insipidus (DI) (75%), headache (67%) and visual field defects (67%) were the most common findings at presentation. Glucocorticoid replacement increased the sensitivity for diagnosis of DI. All cases were contrast enhancing on MRI and the endoscopic trans-sphenoidal approach was preferred for biopsy and debulking.

CONCLUSIONS

The pituitary should not be overlooked as a site of metastasis and sellar symptoms may be the first presentation of neoplastic disease. Any biochemical or clinical sign of pituitary pathology in a patient with known cancer should raise suspicion for sellar metastasis. Moreover, the development of DI or ophthalmoplegia from any pituitary lesion is suggestive of metastatic disease even in patients with no known primary.

Pituitary metastasis: a rare condition

Tumor metastasis to the pituitary gland is a life-threatening condition associated with short life span. Pituitary metastasis is rare, however, and not well-documented. A better understanding of its clinical manifestations could lead to earlier diagnosis, appropriate therapy, and potentially improving quality of life. Therefore, we retrospectively studied the charts of patients with pituitary metastases who were treated at the City of Hope National Medical Center in Duarte, California, from 1984 to 2018. We reviewed and analyzed tumor origin, primary pituitary clinical manifestation, duration between primary tumor diagnosis and pituitary metastasis, type of treatment, and patient survival. A total 11 patients with a mean age of 59.2 years and median survival of 50.33 months were identified. Breast cancer and lymphoma were the most common primary origins in these cases, and diabetes insipidus and panhypopituitarism were the most common primary manifestations of their metastasis. We also compared our results with reports in the literature published between 1957 and 2018. A total 289 patients with pituitary metastasis have been reported in the literature. Breast cancer was the most frequent primary origin of the metastasis, and visual involvement was the most common primary manifestation. The posterior part of the pituitary is more susceptible than the anterior to metastasis. Pituitary metastasis may occur as a consequence of successful primary tumor treatment prolonging the chance of seeding. Future studies are needed to determine the molecular mechanism of metastasis to the pituitary.

Progressive visual disturbance and enlarging prolactinoma caused by melanoma metastasis: A case report and literature review

RATIONALE

Melanoma metastases to the pituitary adenoma (MMPA) are extremely rare, with only 1 reported case. To date, the melanoma metastasis to the existing prolactinoma has not been reported in literatures.

PATIENT CONCERNS

We report a case of 62-year-old woman presented with progressive visual disturbance and hyperprolactinemia. Magnetic resonance imaging demonstrated the presence of a round sellar mass.

DIAGNOSES

Melanoma metastasis to the pituitary adenoma.

INTERVENTIONS

Surgery was performed and intraoperative frozensection examination found melanin granules and histopathological examination confirmed melanoma metastasis to the pituitary adenoma.

OUTCOMES

After surgery, the patient developed widespread melanoma metastasis to lower limbs. Twenty-two months later, the patient was alive with worse symptoms.

LESSONS

We reviewed and analyzed the clinical data, imaging features, and treatment methods of other reported cases of metastases to pituitary adenoma (MPA). This study provides clinical information for the diagnosis and management of MMPA.

Clinical and biochemical characteristic features of metastatic cancer to the sella turcica: an analytical review

BACKGROUND AND OBJECTIVES

Sellar metastasis is uncommon and poorly characterized as published data include small series of subjects. This study's goal is to identify unique features that differentiate this entity from other sellar masses such as pituitary macroadenomas.

METHODS

Published cases of pathologically-confirmed sellar metastasis along with our experience in such patients over a 6-years period were reviewed (total = 129). As a control group, we reviewed similar data on 55 patients with pituitary macroadenomas managed over the same time-period. Presenting symptoms, pituitary dysfunction were analyzed using univariate, multivariate and receiver operating characteristic (ROC) analyses.

RESULTS

Sellar metastasis has equal gender distribution with a median patient-age of 56 years. The most common primary malignancy was breast cancer (29%) in women and lung cancer (30%) in men. Sellar metastasis was the first manifestation of cancer in over 40% of patients. Common presenting symptoms included headaches, visual field deficits, abnormal eye motility and diabetes insipidus. These symptoms were less frequent among patients with pituitary macroadenomas. Univariate regression analyses showed that headaches, abnormal eye motility, visual field deficits and diabetes insipidus were each predictive of metastatic disease. ROC analysis combining all 4 features revealed an AUC of 0.953 with a sensitivity of 0.818 and a specificity of 0.935. Using the multivariate regression, abnormal eye motility and/or diabetes insipidus independently predicted metastatic disease.

CONCLUSIONS

Sellar metastasis should be suspected in patients presenting with sellar masses, abnormal eye motility and/or diabetes insipidus even those without known malignancy since pituitary metastasis can often be the first manifestation of cancer.

Clinical characteristics and pituitary dysfunction in patients with metastatic cancer to the sella

OBJECTIVE

Metastatic disease to the sella is uncommon and there are limited available data regarding the clinical aspects of this disease. We therefore sought to characterize the clinical demographics of sellar metastases.

METHODS

Retrospective chart review of adults treated at Stanford University Medical Center from 1980 to 2011 with metastatic disease to the sella.

RESULTS

A total of 13 subjects were identified (9 females). The mean age at diagnosis was 55 years (range, 25 to 73 years). A total of 6 patients (46%) had breast carcinoma, 3 (23%) had renal cell carcinoma, 2 (15%) had squamous cell carcinoma of the head and neck, 1 had bronchoalveolar carcinoma of the lung, and 1 had nodular sclerosing Hodgkin's lymphoma. The most common presenting signs and symptoms were headache (58%), followed by fatigue (50%), polyuria (50%), visual field defects (42%), and ophthalmoplegia (42%). Seventy-five percent of patients presented with at least one pituitary hormone insufficiency, which included 6 patients (50%) with diabetes insipidus (DI). Eight (67%) subjects had secondary hypothyroidism and 5 (45%) had secondary adrenal insufficiency. Of the patients with stalk involvement, 86% had DI. All patients had a prior diagnosis of malignancy, with a mean duration of 95 months.

CONCLUSION

The most common neoplastic sources to the sella were breast and renal cell carcinomas. Secondary hypothyroidism was the most common endocrine abnormality, followed by DI and adrenal insufficiency. New-onset central hypothyroidism and DI along with known malignancy in a patient with a sellar lesion should raise the suspicion of a metastatic source.

Pituitary apoplexy caused by hemorrhage from pituitary metastatic melanoma: case report

Melanoma metastases to the pituitary gland are extremely rare, with only a few reported cases. We report an unusual case of pituitary metastatic melanoma in which the patient presented with pituitary apoplexy. A 68-year-old man presented general fatigue and anorexia following sudden headache. Neurological examination disclosed bitemporal hemianopsia. Computed tomography (CT) scans revealed a suprasellar mass including intratumoral hematoma. Magnetic resonance (MR) images demonstrated a circumscribed mass lesion in the intra- and suprasellar regions, compressing the optic chiasm. Surgical exploration was performed through a transsphenoidal approach, and a mixture of tumor and necrotic tissue with old hematoma was obtained. The histological examination of the specimen revealed a partly necrotic, malignant tumor with focal melanotic pigmentation. Histopathologically, the diagnosis was consistent with pituitary apoplexy caused by hemorrhage from pituitary metastatic melanoma.

Stereotactic radiosurgery for malignant extracerebral intracranial tumors: patient selection, efficacy, and technical nuances

Intracranial tumors extrinsic to the brain include a variety of histological types, including meningiomas and pituitary tumors, both of which are most commonly benign but can present with malignant biology and clinical behavior. In the same compartment arise a number of frankly malignant tumors, which include chordomas, metastases (to bone or dura), and sarcomas (e.g., chondrosarcoma). These malignant tumors derive from bone, dura, or vascular elements and pose significant therapeutic challenges. Because of the anatomical constraints imposed by the cranial base and by venous sinuses, and because of the relentless tendency to recur shown by malignant tumors of meningeal origin, surgery often achieves incomplete removal. Some tumors are not resectable without the use of complex approaches that endanger adjacent neurovascular structures. For these reasons, stereotactic radiosurgery (SRS) has an important role in primary treatment of malignant intracranial extracerebral tumors and, most commonly, in treating residual or recurrent disease after resection has established the diagnosis and decompressed the tumor's environs. Here we review the role and technique of SRS in a variety of these unusual lesions, including malignant meningioma, glomus tumor, pituitary carcinoma, skull base metastasis, chordoma, and chondrosarcoma. Understanding the specific nuances of each is helpful in allowing optimal planning of patient selection, dose level, and dose contours for best treatment results. Currently, SRS can be useful in achieving effective palliation of these malignant tumors but does not usually provide a cure. In the future, better results are anticipated because of new methods of metabolic imaging for delineating tumor extent and new radiosensitizers that enhance tumor kill within a safe range of doses at the tumor margin.

Sellar and parasellar metastatic tumors

The sellar and parasellar (SPS) region is a complex area rich in vital neurovascular structures and as such may be the location of first manifestation of a systemic malignancy. Metastases to this region are rare; breast cancer is the most common source among those that metastasize to the SPS region. Ophthalmoplegia, headache, retroorbital or facial pain, diabetes insipidus, and visual field defects are the most commonly reported symptoms. Lack of specific clinical and radiological features renders SPS metastases difficult to differentiate from the other frequently encountered lesions in this area, especially when there is no known history of a primary disease. Currently accepted management is multimodality therapy that includes biopsy and/or palliative surgical resection, radiation, and chemotherapy. Although no significant survival benefits have been shown by the surgical series, surgical resection may improve quality of life. Here we review the relevant literature and present six illustrative cases from our own institution.

Efficacy of Trans-septal Trans-sphenoidal Surgery in Correcting Visual Symptoms Caused by Hematogenous Metastases to the Sella and Pituitary Gland

The rate of symptomatic improvement of visual symptoms associated with hematogenous metastases to the sella and pituitary was evaluated retrospectively in seven patients (five men, two women; mean age, 52.3 years) with primarily visual symptoms (diplopia alone in three, diplopia with blurred vision in one, blurred vision alone in one, loss of peripheral vision in one, and unilateral complete blindness in one). Symptom duration ranged from 0.5 to 2 months. The primary diseases were non-small cell lung cancer in two patients, renal cell carcinoma in two patients, prostate cancer in two patients, and medullary thyroid carcinoma in one patient. All patients had widespread metastatic disease. Three patients had a suprasellar tumoral component. One patient had a clival extension, and one patient had extension into the cavernous sinus. All underwent trans-sphenoidal surgery to correct visual symptoms. Gross total resection was achieved in three patients. Subtotal resections and a partial resection were performed in three patients and one patient, respectively. Surgical blood loss averaged 282 mL. One patient died from sepsis. Five patients developed complications (cerebrospinal fluid leakage in three, diabetes insipidus in two, anterior pituitary dysfunction in two, and colitis in one). At a mean follow-up of 15 months, three patients were alive. Visual symptoms improved in five patients and were unchanged in two. Trans-sphenoidal surgery helped improve visual symptoms in most patients. The morbidity rate was high and likely related to the locally destructive and extensive nature of the lesions in overall morbid patients with widespread metastatic disease. Unless nonoperative measures can provide equal results, however, this approach provides reasonable palliation.

Melanoma of the sellar region

Metastatic melanoma has a propensity for multiple intra cranial deposits. Rarely, metastatic melanoma to the pituitary gland has been reported, usually in conjunction with widespread systemic metastases. We describe a patient with metastatic melanoma to the pituitary gland as the first clinical presentation of widespread metastatic disease and review the relevant literature.

Intracranial metastatic disease rarely involves the pituitary: retrospective analysis of 935 metastases in 155 patients and review of the literature

We present a case report of a patient recently treated at our institution for an isolated non-small cell lung cancer metastatic lesion to the sella, report the lack of involvement of the pituitary gland in a large single-institution series of treated intracranial parenchymal metastases, and review the pertinent literature. We reviewed cranial imaging studies (CT and MRI) for 935 metastases in 155 patients treated at our institution over the previous 3 years for intracranial metastatic disease. Special attention was paid to the skull base to document the presence of any metastatic disease involving the pituitary gland, infundibular stalk, sella turcica (including anterior and posterior clinoids), or diaphragm sellae. We found no other involvement of the pituitary gland or other sellar structures by metastatic disease in this series. Intracranial metastatic disease rarely involves the pituitary gland and infundibular stalk parenchyma, suggesting that this structure may be safely omitted from the treatment field during WBRT and prophylactic cranial irradiation (PCI). This treatment approach should reduce the late sequelae of treatment to this critical organ.