Atypical cystic carcinoid tumors of the liver

Surgical and oncologic outcomes for liver resections of cystic neuroendocrine tumor liver metastasis

BACKGROUND

Cystic neuroendocrine tumor liver metastases (NETLM) are rare and dynamics in the liquid compartment often misinterpreted as rapid progression, affecting selection for liver resection candidates. This study retrospectively evaluates surgical and oncologic outcomes in patients with cystic versus solid NETLM from small bowel and pancreatic primaries.

METHODS

Between 2000 and 2020, 12 patients with cystic NETLM were identified among 464 patients who underwent >90 % tumor cytoreduction debulking hepatectomy at the Mayo Clinic. Tumor and patient characteristics, as well as surgical and oncologic outcomes, were compared with the total cohort of patients with solid NETLM, including a propensity-matched cohort.

RESULTS

Patients with cystic NETLM were similar in age (55.4 vs. 59.7 years; p = 0.113) and sex (58 % vs. 51 % men; p = 0.772) to those with solid NETLM. Synchronous metastases (92 % vs. 77 %; p = 0.314), bilobar distribution (83 % vs. 79 %; p = 1.000), lesion numbers (p = 0.547), Ki67 % expression (p = 0.311), and extrahepatic lesions (8 % vs. 18 %; p = 0.702) were similar. Cystic metastases were larger (7.3 vs. 3.8 cm; p < 0.001). Surgical risk did not differ, with major morbidity (25 % vs. 22 %; p = 0.729) and mortality (0 % vs. <2 %; p = 1.000). Median overall survival (OS) was 13.8 vs. 10.6 years (p = 0.513), and hepatic-progression-free survival (PFS) was 0.71 vs. 1.78 years (p = 0.507). Matched cohorts showed no significant difference in OS (13.80 vs. 8.57; p = 0.316) or hepatic-PFS (0.71 vs. 1.33; p = 0.620).

CONCLUSION

Surgical risk and long-term outcomes do not significantly differ between cystic and solid NETLMs. Given excellent long-term survival rates with >90 % cytoreduction, radical debulking is advised for both phenotypes when clinically feasible.

Liver metastasis mimicking an abscess

Hepatic metastases from carcinoid tumours are typically solid, hypervascular lesions on imaging. The cystic form, mimicking an abscess, is extremely rare. We report a case of a 48-year-old female presenting with a large hepatic mass that was diagnosed as a hepatic abscess, but the ultrasound-guided biopsy showed well-differentiated grade 1 neuroendocrine tumour. CT scan of chest, abdomen and pelvis was performed, looking for the primary tumour, it revealed an endobronchial mass of the right inferior lobe. Lung biopsy by rigid bronchoscopy was taken confirming the diagnosis of a typical carcinoid tumour.

Pseudocystic appearance of an orbital carcinoid metastasis

Carcinoid tumours are a low-grade neuroendocrine malignancy that infrequently metastisizes to orbital structures. The typical radiological appearance of carcinoid is a solid, well-circumscribed mass that enhances with contrast. We present a case of orbital carcinoid metastasis with pseudocystic radiological appearance and review of the literature.

A case of pseudocystic liver metastases from an atypical lung carcinoid tumor

Metastatic neuroendocrine tumors of the liver typically appear as solid, hypervascular masses on imaging. Pseudocysts mimicking simple cysts are extremely rare. A 42-year-old Japanese woman was referred with a single pulmonary mass in the left lower lobe. No metastatic lesion was detected and no occupying lesion in the liver was observed. The lung tumor was diagnosed as an atypical carcinoid. Postoperative investigation revealed new hepatic simple cysts in the liver, which increased in size over time and changed into hemorrhagic cysts. Fluorodeoxyglucose positron emission tomography and somatostatin receptor scintigraphy using 111In-octreotide demonstrated no accumulation in the liver. Our patient did not have symptoms consistent with carcinoid syndrome. The patient underwent partial resection of the cystic lesions of the liver. Gross examination of the tumors demonstrated thin-wall cavitated lesions with hemorrhage which were metastases from the atypical carcinoid of the lung. When a growing cystic lesion with intracystic hemorrhage is found in the liver of a patient with a history of carcinoid tumors, pseudocysts caused by degeneration of a carcinoid metastasis should be considered as a differential diagnosis.

Two Cases of Primary Hepatic Neuroendocrine Tumors and a Review of the Current Literature

Neuroendocrine tumors comprise approximately 1-2% of all gastrointestinal tumors, and while the liver is the most common site for metastasis of these tumors, primary hepatic neuroendocrine tumors are very rare entities. Since first being reported in 1958, there have been less than 150 cases reported in the literature. Because of the infrequent occurrence of these tumors, the pool of data available for analysis regarding these tumors is small. As such, the medical community must rely on the publication of case report data to further enlarge this data pool, with the hopes of eventually having enough data to draw meaningful, statistically significant conclusions with regard to diagnosis and management of these rare tumors. We have encountered two patients at our institution within the last year with primary hepatic neuroendocrine tumors. We present their cases in this manuscript in an effort to contribute to the available data on the disease. We also provide a concise review of the literature available to date regarding primary hepatic neuroendocrine tumors.

Prevalence of hepatic lesion types defined by T2-weighted and dynamic gadolinium-enhanced MR imaging in patients with metastasized neuroendocrine tumors

PURPOSE

Identifying liver metastases from neuroendocrine tumors (NETs) is a pretherapeutic challenge in patients who are candidates for liver resection. The aims of our study are to characterize and determine the frequency of different MRI characteristics of liver metastases caused by NETs in a lesion-by-lesion analysis and to determine the frequency of monomorphous and polymorphous metastases in a patient-by-patient analysis.

METHODS

This retrospective study involved 47 patients with liver metastases arising from histologically confirmed NETs. In a lesion-by-lesion analysis, we classified these metastases according to their MRI characteristics as follows: hypervascular lesions with homogeneous or peripheral enhancement, hypovascular lesions, pure cystic lesions, and mixed solid/cystic lesions. In the patient-by-patient analysis, we distinguished patients whose metastases had the same MRI characteristics from patients with mixed lesion characteristics.

RESULTS

A total of 376 metastases were analyzed. Of these, 84.3% (n = 317) were hypervascular, with 51.9% showing homogeneous enhancement and 32.4% (n = 122) showing peripheral enhancement. Another 7.4% (n = 28) were hypovascular, 5.3% (n = 20) were pure cystic, and 2.9% (n = 11) were mixed solid/cystic. After excluding three patients with solitary lesions, 40.9% of patients (n = 18) had mixed-type lesions, consisting of hypervascular lesions with either homogeneous or peripheral enhancement in 27.3% of cases (n = 12), while 59.1% of patients (n = 26) had identical lesions.

CONCLUSION

Approximately 15% of metastases have atypical MRI characteristics and are either hypovascular or cystic. Metastases with different MRI characteristics coexist in 40% of patients.

Imaging findings of primary hepatic carcinoid tumor with an emphasis on MR imaging: case study

Carcinoid tumors are slow-growing tumors originating in the neuroendocrine cells, and occur most frequently within the gastrointestinal tract. Although the liver is the most common site for metastatic carcinoid tumors, primary hepatic carcinoid tumors are exceedingly rare and reports of the imaging findings have been very scarce. We herein report imaging findings with an emphasis on magnetic resonance imaging in two cases of primary hepatic carcinoid tumors. In both cases, the tumors showed cystic areas with hemorrhagic components and early enhanced solid areas.

Hepatic pseudocystic metastasis of well-differentiated ileal neuroendocrine tumor: a case report with review of the literature

Imaging appearance of cyst-like changes is most frequently described in primary neuroendocrine lesions, especially pancreatic NETs.The imaging finding of a pseudocystic lesion of the liver puts in differential diagnosis many pathologies such as infectious diseases, simple biliary cysts up to biliary cystadenomas and eventually to primary or metastatic malignancies.Primary or metastatic hepatic malignancies with pseudocystic aspects are rare, and a pseudocystic aspect is reported only after neo-adjuvant treatment.Liver metastasis of untreated neuroendocrine tumors are usually solid and, to our knowledge, only two cases of neuroendocrine cystic hepatic metastases of ileal atypical carcinoids have been reported so far.We present a case of a 67 years old man with synchronous finding of an untreated hepatic pseudocystic lesion and an ileal mass histologically diagnosed as a well differentiated (G1) neuroendocrine tumor.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1443883503102967.