Esophageal carcinoid tumor (neuroendocrine tumor, NET) is a rare neoplasm arising from esophageal neuroendocrine cells, constituting less than 1% of all esophageal tumors. It is the rarest site for gastrointestinal carcinoid tumors. Histologically originates from enterochromaffin cells or enterochromaffin-like cells. Typically occurs between ages 50-70 with male predominance. Tumors are submucosal in location and tend to grow as polypoid intraluminal masses. Low-grade (G1-G2) carcinoids have an indolent course, whereas high-grade neuroendocrine carcinomas (G3) demonstrate aggressive behavior with poor prognosis. Carcinoid syndrome is extremely rare in esophageal location as serotonin is metabolized in the liver via portal drainage. On CT, it appears as a hypervascular submucosal mass; functional imaging with somatostatin receptor scintigraphy (Octreoscan) or Ga-68 DOTATATE PET/CT plays an important role in diagnosis.
Age Range
40-70
Peak Age
55
Gender
Male predominant
Prevalence
Rare
Esophageal carcinoid tumors originate from diffuse neuroendocrine system cells (particularly enterochromaffin cells) located in the lamina propria of the esophageal mucosa. These cells normally secrete serotonin, chromogranin A, and other neuropeptides that regulate gastrointestinal motility and secretion. In neoplastic transformation, cell proliferation control mechanisms are disrupted, with genetic alterations often involving MEN1 gene mutations or chromosome 18q deletions playing a role. The tumor develops in the submucosa and forms a polypoid intraluminal mass with progressive growth. Hypervascularity is a characteristic feature of neuroendocrine tumors, and intense capillary network formation through VEGF expression causes prominent enhancement in the arterial phase on CT. Somatostatin receptors (especially types 2 and 5) are densely expressed on tumor cells; this allows radioactive somatostatin analogs (111In-pentetreotide or 68Ga-DOTATATE) to bind to tumor cells, producing distinctly positive findings on scintigraphic/PET imaging. Low-grade tumors (Ki-67 <3%) demonstrate slow growth and low metastatic risk, while high-grade neuroendocrine carcinomas (Ki-67 >20%) exhibit rapid proliferation, extensive necrosis, and early metastasis — this necrosis manifests as heterogeneous enhancement and central low-density areas on imaging.
A submucosal mass showing prominent hypervascular enhancement in arterial phase on CT combined with intense somatostatin receptor uptake on Ga-68 DOTATATE PET/CT is a diagnostic combination for esophageal carcinoid tumor (NET).
Well-defined submucosal polypoid mass showing prominent homogeneous enhancement in arterial phase. In low-grade tumors, enhancement is homogeneous and intense; in high-grade tumors, heterogeneous enhancement may be observed due to necrotic areas. The tumor typically grows toward the esophageal lumen creating an intraluminal filling defect. Esophageal wall layers are preserved and transmural invasion is rare in low-grade tumors.
Report Sentence
Well-defined submucosal polypoid mass in the esophagus demonstrating prominent homogeneous arterial phase enhancement is observed; neuroendocrine tumor (carcinoid) should be the leading consideration given its hypervascular characteristics.
Tumor enhancement persists in the portal venous phase but may show mild decrease compared to the arterial phase. This progressive enhancement pattern (prominent arterial, persistent portal venous) is typical for low-grade NETs. Washout may be more pronounced in high-grade tumors. Periesophageal fat planes are usually preserved.
Report Sentence
The mass demonstrates persistent enhancement in the portal venous phase; this progressive enhancement pattern is consistent with neuroendocrine tumor.
Intense somatostatin receptor uptake in the esophageal mass on Ga-68 DOTATATE PET/CT (SUVmax typically >15-20). Low-grade (G1-G2) tumors show more intense DOTATATE uptake as somatostatin receptor expression is higher. In high-grade (G3) tumors, DOTATATE uptake may decrease; FDG PET/CT is more useful in this situation (flip-flop phenomenon). Also plays a critical role in detecting distant metastases (liver, bone, lymph node).
Report Sentence
Intense somatostatin receptor uptake is observed in the esophageal mass on Ga-68 DOTATATE PET/CT; this finding confirms the diagnosis of neuroendocrine tumor.
On endoscopic ultrasound (EUS), well-defined, homogeneous hypoechoic, oval or round mass originating from the submucosal layer (3rd layer — hypoechoic) of the esophageal wall. Muscularis layer (4th layer) is usually intact and separate from the tumor. In low-grade tumors, internal structure is homogeneous with smooth borders. In high-grade tumors, irregular borders, heterogeneous echo pattern, and muscularis layer invasion may be seen. Tissue diagnosis is obtained through EUS-guided fine needle aspiration (FNA) or core biopsy.
Report Sentence
On EUS, a well-defined, homogeneous hypoechoic mass originating from the submucosal layer of the esophageal wall is observed; the muscularis layer is intact, consistent with submucosal neuroendocrine tumor.
The tumor shows intermediate-to-hyperintense signal on T2-weighted images. In low-grade tumors, signal is relatively homogeneous while in high-grade tumors, heterogeneous signal may be observed due to necrosis and hemorrhage areas. The submucosal location of the tumor allows high-contrast evaluation of esophageal wall layers on MRI. Periesophageal fat planes are preserved.
Report Sentence
The esophageal mass shows intermediate-to-hyperintense signal on T2-weighted images; its submucosal location and signal characteristics are consistent with neuroendocrine tumor.
The tumor shows high signal on diffusion-weighted imaging (DWI) with low values on ADC map (typically <1.2 x 10-3 mm2/s). Diffusion restriction reflects the high cellularity of the tumor. In high-grade tumors, diffusion restriction may be more pronounced (lower ADC values). DWI provides additional information to enhancement data in distinguishing the tumor from surrounding normal tissue.
Report Sentence
The esophageal mass demonstrates diffusion restriction (low ADC values) on diffusion-weighted imaging, indicating high cellularity.
I-123 MIBG scintigraphy shows variable uptake in esophageal carcinoid tumors. MIBG is a norepinephrine analog taken up through the catecholamine storage mechanism of neuroendocrine cells. MIBG sensitivity is low in gastrointestinal NETs (50-60%); somatostatin receptor imaging (Octreoscan or DOTATATE PET) is superior. However, MIBG provides information in pheochromocytoma differential diagnosis.
Report Sentence
Variable uptake is observed in the esophageal mass on I-123 MIBG scintigraphy; correlation with somatostatin receptor imaging is recommended.
Criteria
Well-differentiated neuroendocrine tumor. Slow growth, low mitotic activity, low Ki-67 index. 5-year survival >90%.
Distinct Features
Homogeneous hypervascular enhancement on CT, smooth borders, no necrosis. Intense uptake on DOTATATE PET. Homogeneous hypoechoic mass on EUS.
Criteria
Well-differentiated neuroendocrine tumor but increased proliferation. Moderate mitotic activity, intermediate Ki-67 index. 5-year survival 65-80%.
Distinct Features
Heterogeneous enhancement may begin on CT, mildly irregular borders. DOTATATE PET still positive but may be less intense than G1. Size generally larger than G1.
Criteria
Poorly differentiated neuroendocrine carcinoma. Aggressive behavior, rapid growth, early metastasis. Small cell or large cell morphology. 5-year survival <30%.
Distinct Features
Markedly heterogeneous enhancement on CT, central necrosis, irregular borders, surrounding tissue invasion. DOTATATE PET may be negative — FDG PET positive (flip-flop). Regional and distant metastasis common.
Criteria
Both components (neuroendocrine and non-neuroendocrine) constitute at least 30% of the total tumor. Usually adenocarcinoma + neuroendocrine carcinoma combination.
Distinct Features
Heterogeneous mass on CT — may show different enhancement patterns. Both DOTATATE and FDG uptake possible on PET (dual avidity). May be indistinguishable from pure NET on imaging; definitive diagnosis is pathological.
Distinguishing Feature
Leiomyoma originates from the muscularis layer (4th layer) and appears as a homogeneous, mildly enhancing mass on CT — unlike the hypervascular enhancement of carcinoid, it does not show prominent enhancement. Differentiated on EUS as a hypoechoic mass originating from the 4th layer.
Distinguishing Feature
GIST originates from the muscularis layer, is generally larger and may show exophytic growth. Heterogeneous enhancement and cystic/necrotic degeneration are common on CT. c-KIT (CD117) positive, DOTATATE PET negative.
Distinguishing Feature
SCC is mucosal in origin and presents as irregular wall thickening/mass — different from the well-defined submucosal mass of carcinoid. SCC is more heterogeneous, less vascular. DOTATATE PET negative, FDG PET positive.
Distinguishing Feature
Granular cell tumor is submucosal on EUS and may appear similar to carcinoid, but is generally smaller (<2 cm) and shows mild enhancement — different from hypervascular enhancement of carcinoid. DOTATATE PET negative, S-100 positive.
Urgency
urgentManagement
surgicalBiopsy
NeededFollow-up
specialist-referralWhen esophageal carcinoid tumor is detected, histological confirmation and grade determination through endoscopic biopsy is required. Low-grade (G1) small tumors (<1 cm) can be treated with endoscopic mucosal resection. Staging with Ga-68 DOTATATE PET/CT is performed for G1-G2 tumors. Advanced stage or large tumors require surgical resection (esophagectomy). Cisplatin-based chemotherapy is administered for G3 neuroendocrine carcinomas. Somatostatin analogs (octreotide, lanreotide) are used for functional tumors and antiproliferative purposes. Multidisciplinary tumor board evaluation is recommended.
Small (<1 cm) esophageal carcinoid tumors can be treated with endoscopic resection. Larger tumors require surgical resection. Carcinoid syndrome may develop with liver metastasis. Somatostatin receptor scintigraphy is used for staging.