Primary functioning hepatic paraganglioma mimicking hepatocellular carcinoma: A case report and literature review

Hepatic and perihepatic PEComas: A study describing a series of five rare cases

BACKGROUND

Perivascular epithelioid cell tumors (PEComas) encompass a group of rare mesenchymal neoplasms, with dual melanocytic and muscular differentiation. Hepatic PEComas are rare and difficult to diagnose, and their behavior is still unclear.

MATERIALS AND METHODS

Herein, we report a total of five cases of hepatic and perihepatic PEComas over a period of the last 5 years from our and collaborating center's archive. A detailed histological evaluation was done. A comprehensive panel of immunohistochemical stains was used and fluorescence in-situ hybridization analysis was performed for the TFE3 gene using break-apart probes.

RESULT

All these patients were women, with an average age of presentation of 44 years. The lesions were in the right hepatic lobe: three cases, the left hepatic lobe: one case, and gastrohepatic ligament: one case. The preoperative clinicoradiological diagnoses were hepatocellular carcinoma (HCC), focal nodular hyperplasia, hemangioma, metastasis, and gastrointestinal stromal tumor, respectively. Surgical excision was performed in four cases with no further adjuvant therapy. Histopathological examination and subsequent immunophenotyping revealed a diagnosis of PEComa. Fluorescence in-situ hybridization analysis was performed for TFE3 gene rearrangement in four cases.

CONCLUSIONS

This series highlights the fact that accurate histological diagnosis of hepatic or perihepatic PEComas is important to prevent unnecessary aggressive treatment, unlike primary hepatocellular carcinomas or hepatoid/epithelioid metastatic tumors.

Primary hepatic paraganglioma with megacolon: A case report

Primary hepatic paraganglioma (PGL) is a rare neuroendocrine tumor characterized by clinical manifestations including paroxysmal hypertension, palpitation, abdominal pain and constipation. In the present study, the case of a 21-year-old woman with pathologically confirmed hepatic PGL with megacolon following surgery is reported. The patient initially visited Beijing Tiantan Hospital (Beijing, China) for hypoferric anemia. A triple-phase CT scan of the whole abdomen showed a large hypodense mass with a solid periphery and strong arterial enhancement of the peripheral solid portion of the liver. The sigmoid colon and rectum were obviously distended, filled with gas and intestinal contents. The patient was preoperatively diagnosed with iron deficiency anemia, liver injury and megacolon and then underwent partial hepatectomy, total colectomy and enterostomy. Microscopically, the liver cells exhibited an irregular zellballen pattern. In addition, immunohistochemical staining revealed that liver cells were positive for CD56, chromogranin A, vimentin, S-100, melan-A and neuron-specific enolase. Therefore, the diagnosis of primary PGL of the liver was confirmed. These findings suggested that primary hepatic PGL should not be excluded when megacolon occurs and comprehensive imaging evaluation is of great importance for its diagnosis.

Paraganglioma arising from the liver and abutting the heart

A paraganglioma is a rare extra-adrenal neuroendocrine tumour with a variable clinical presentation. A paraganglioma can arise anywhere along the sympathetic and parasympathetic chains, but it can occasionally emerge from unusual locations such as the liver and the thoracic cavity. We report a rare case of a woman in her 30s who presented to our emergency department with symptoms of chest discomfort, episodic hypertension, tachycardia and diaphoresis. A diagnostic approach including a chest X-ray, an MRI and a positron emission tomography-CT scan showed a large exophytic liver mass protruding into the thoracic cavity. For further characterisation of the mass, a biopsy of the lesion was performed, demonstrating that the tumour is of neuroendocrine origin. This was supported by a urine metanephrine test showing high levels of catecholamine breakdown products. Treatment consisted of a unique multidisciplinary approach involving hepatobiliary and cardiothoracic surgery allowing a safe and complete extermination of the hepatic tumour and its cardiac extension.

The Complex Histopathological and Immunohistochemical Spectrum of Neuroendocrine Tumors-An Overview of the Latest Classifications

Neuroendocrine neoplasms (NENs) originate from the neuroendocrine cell system, which may either take the shape of organoid cell aggregations or be composed of dispersed cells across various organs. Therefore, these tumors are heterogenous regarding the site of origin, functional status, degree of aggressiveness, and prognosis. When treating patients with neuroendocrine tumors, one of the most significant challenges for physicians is determining the correct tumor grade and thus classifying patients into risk categories. Over the years, the classification of these tumors has changed significantly, often causing confusion due to clinical, molecular, and immunohistochemical variability. This review aims to outline the latest NENs classifications regardless of their site of origin. Thus, an overview of the key histopathological and immunohistochemical characteristics of NENs could pave the way to validate possible predictive and prognostic markers and also guide the therapeutic conduct.

Primary Functioning Hepatic Paraganglioma Treated by Laparoscopy: A Case Report

Paragangliomas are highly vascularised and often heritable tumors derived from the paraganglia. They are typically discovered in the retroperitoneal space as well as the head and neck region but are rarely encountered in the liver parenchyma. We report a case of a primary functioning hepatic paraganglioma and provide an up-to-date literature review of patients with such tumors. We present a case of functioning paraganglioma in a 34-year-old female patient who suffered a solitary lesion in her left lateral lobe with symptoms of hypertension since pregnancy. She did not have any family history and her pre-pregnancy examination was negative. An abdominal CT imaging revealed a 6.5 × 5.7 cm liver lesion in segments II and III. Laboratory investigations identified elevation in plasma-free catecholamines. With sufficient preoperative preparation, the patient underwent laparoscopic left hemihepatectomy. Immunohistochemical staining revealed Syn (+) tumor cell nests surrounded by S-100 sustentacular cells (+), providing a definitive diagnosis of paraganglioma. The patient recovered uneventfully without signs of recurrence during a 1-year follow-up period. Our case demonstrates that primary refractory hypertension in pregnancy should be screened for paraganglioma through abdominal ultrasound and plasma free catecholamines. On the other hand, laparoscopic surgery is technically safe and feasible for the treatment of patients with hepatic paragangliomas in favorable locations.

Tumour to tumour metastasis: case of a carotid body paraganglioma metastatic to a hepatocellular adenoma

Tumour to tumour metastases are uncommon, and we report a case of carotid body paraganglioma metastatic to a hepatocellular adenoma. A 54-year-old man presented after a CT chest for chronic cough that incidentally identified two liver lesions in segment 3 and caudate. The imaging findings were suspicious for atypical haemangiomas versus hepatocellular adenoma. The segment 3 lesion was biopsied, demonstrating beta-catenin activated hepatocellular adenoma. He underwent partial hepatectomy with pathology showing the beta-catenin activated hepatocellular adenoma contained a central area of paraganglioma. On closer review, the patient revealed a carotid body paraganglioma with lymph node metastases requiring resection 24 years earlier. He subsequently underwent left hepatectomy including the resection bed and caudate, which confirmed the caudate lesion as metastatic paraganglioma. This case demonstrates how paraganglioma can metastasise to liver decades after initial resection and provide insight into the diagnostic workup for hepatocellular adenoma with neuroendocrine features.

Pediatric Metastatic Pheochromocytoma and Paraganglioma: Clinical Presentation and Diagnosis, Genetics, and Therapeutic Approaches

Although pediatric pheochromocytomas and paragangliomas (PPGLs) are rare, they have important differences compared to those in adults. Unfortunately, without timely diagnosis and management, these tumors have a potentially devastating impact on pediatric patients. Pediatric PPGLs are more often extra-adrenal, multifocal/metastatic, and recurrent, likely due to these tumors being more commonly due to a genetic predisposition than in adults. This genetic risk results in disease manifestations at an earlier age giving these tumors time to advance before detection. In spite of these problematic features, advances in the molecular and biochemical characterization of PPGLs have heralded an age of increasingly personalized medicine. An understanding of the genetic basis for an individual patient's tumor provides insight into its natural history and can guide clinicians in management of this challenging disease. In pediatric PPGLs, mutations in genes related to pseudohypoxia are most commonly seen, including the von Hippel-Lindau gene (VHL) and succinate dehydrogenase subunit (SDHx) genes, with the highest risk for metastatic disease associated with variants in SDHB and SDHA. Such pathogenic variants are associated with a noradrenergic biochemical phenotype with resultant sustained catecholamine release and therefore persistent symptoms. This is in contrast to paroxysmal symptoms (e.g., episodic hypertension, palpitations, and diaphoresis/flushing) as seen in the adrenergic, or epinephrine-predominant, biochemical phenotype (due to episodic catecholamine release) that is commonly observed in adults. Additionally, PPGLs in children more often present with signs and symptoms of catecholamine excess. Therefore, children, adolescents, and young adults present differently from older adults (e.g., the prototypical presentation of palpitations, perspiration, and pounding headaches in the setting of an isolated adrenal mass). These presentations are a direct result of genetic determinants and highlight the need for pediatricians to recognize these differences in order to expedite appropriate evaluations, including genetic testing. Identification and familiarity with causative genes inform surveillance and treatment strategies to improve outcomes in pediatric patients with PPGL.

Paraganglioma masquerading as a primary liver lesion: A rare entity discovered during surgery

A 54-year-old woman with controlled hypertension presented with abdominal pain and weight loss. Imaging revealed a 6.6 cm liver lesion. During resection, she became severely hypertensive and diagnosis was paraganglioma. Hepatic paragangliomas are exceedingly rare but must be considered in the differential of abdominal mass even without typical clinical symptoms.

Current Management of Pheochromocytoma/Paraganglioma: A Guide for the Practicing Clinician in the Era of Precision Medicine

Pheochromocytomas and paragangliomas (PCC/PGLs) are rare, mostly catecholamine-producing neuroendocrine tumors of the adrenal gland (PCCs) or the extra-adrenal paraganglia (PGL). They can be separated into three different molecular clusters depending on their underlying gene mutations in any of the at least 20 known susceptibility genes: The pseudohypoxia-associated cluster 1, the kinase signaling-associated cluster 2, and the Wnt signaling-associated cluster 3. In addition to tumor size, location (adrenal vs. extra-adrenal), multiplicity, age of first diagnosis, and presence of metastatic disease (including tumor burden), other decisive factors for best clinical management of PCC/PGL include the underlying germline mutation. The above factors can impact the choice of different biomarkers and imaging modalities for PCC/PGL diagnosis, as well as screening for other neoplasms, staging, follow-up, and therapy options. This review provides a guide for practicing clinicians summarizing current management of PCC/PGL according to tumor size, location, age of first diagnosis, presence of metastases, and especially underlying mutations in the era of precision medicine.

The Diagnosis and Clinical Significance of Paragangliomas in Unusual Locations

Paragangliomas are neuroendocrine neoplasms, derived from paraganglia of the sympathetic and parasympathetic nervous systems. They are most commonly identified in the head and neck, being most frequent in the carotid body, followed by jugulotympanic paraganglia, vagal nerve and ganglion nodosum, as well as laryngeal paraganglia. Abdominal sites include the well-known urinary bladder tumors that originate in the Organ of Zuckerkandl. However, other unusual sites of origin include peri-adrenal, para-aortic, inter-aortocaval, and paracaval retroperitoneal sites, as well as tumors in organs where they may not be expected in the differential diagnosis of neuroendocrine neoplasms, such as thyroid, parathyroid, pituitary, gut, pancreas, liver, mesentery, lung, heart and mediastinum. The distinction of these lesions from epithelial neuroendocrine neoplasms is critical for several reasons. Firstly, the determination of clinical and biochemical features is different from that used for epithelial neuroendocrine tumors. Secondly, the genetic implications are different, since paragangliomas/pheochromocytomas have the highest rate of germline susceptibility at almost 40%. Finally, the characterization of metastatic disease is unique in these highly syndromic lesions. In this review, we summarize updated concepts by outlining the spectrum of anatomic locations of paragangliomas, the importance of morphology in establishing the correct diagnosis, the clinical implications for management, and the impact of genetics on the distinction between multifocal primary tumors compared with malignant disease.