Primary esophageal melanoma is an extremely rare and aggressive malignancy arising from esophageal melanocytes; it constitutes <0.5% of all esophageal malignancies and 0.1-0.2% of all melanomas. Typically occurs in the distal and middle esophagus, more frequently in males aged 60-70 years. Melanocytes originate embryologically from the neural crest and can be found in normal esophageal mucosa (melanosis). Due to melanin pigment, it shows characteristic hyperintense signal on T1-weighted MRI — this is considered a pathognomonic imaging finding for melanoma. It has an extremely aggressive course; metastases are present in 40-80% of patients at diagnosis. Five-year survival rate is below 5%. Treatment is primarily wide surgical resection, although immunotherapy and targeted therapies (BRAF inhibitors) show promising results.
Age Range
45-80
Peak Age
60
Gender
Male predominant
Prevalence
Rare
Esophageal melanoma arises from melanocytes in the esophageal mucosa. Melanocytes originate embryologically from the neural crest and can be found in small numbers throughout the gastrointestinal tract; malignant transformation occurs on the background of melanosis (melanocyte hyperplasia) in the lower and middle esophagus. Melanin synthesis is catalyzed by the tyrosinase enzyme, and melanin polymer accumulates within melanosomes. This melanin accumulation forms the basis of MR imaging: melanin contains paramagnetic free radicals that shorten T1 relaxation time, producing hyperintense signal on T1-weighted images. It also shortens T2 relaxation time, causing T2 hypointensity. The intense neovascularity of the tumor is due to VEGF and IL-8 secreted by melanoma cells, which causes prominent hypervascular enhancement on CT. In amelanotic variants, melanin production is minimal and typical MR signal characteristics may not be seen — this complicates diagnosis. Hematogenous spread occurs early, with liver, lung, and brain being the most common metastatic sites.
Markedly hyperintense signal of the tumor on T1-weighted images — produced by the paramagnetic effect of stable free radicals in melanin pigment shortening T1 relaxation time. This finding can be differentiated from fat with fat suppression and is pathognomonic for melanoma. Not seen in amelanotic variants.
On T1-weighted images, the tumor shows markedly hyperintense signal — this is due to the paramagnetic property of melanin pigment within melanosomes. Signal intensity may be similar to or higher than fat tissue. Homogeneous hyperintensity is typical in melanotic variants; in amelanotic variants (10-30%) this finding is absent and the tumor shows isointense or hypointense signal. Post-contrast T1 demonstrates prominent heterogeneous enhancement.
Report Sentence
The esophageal mass shows markedly hyperintense signal on T1-weighted sequence; this finding consistent with the paramagnetic effect of melanin pigment strongly supports the diagnosis of primary esophageal melanoma.
On T2-weighted images, the tumor shows hypointense signal — due to the T2 shortening effect of melanin pigment. This combination of T1 hyperintense + T2 hypointense signal is highly typical for melanoma and distinguishes from hemorrhagic lesions (like methemoglobin). In amelanotic variants, T2 signal may be variable and hypointensity may not be observed.
Report Sentence
The mass shows hypointense signal on T2-weighted sequence; combined with T1 hyperintensity, this signal pattern is consistent with melanin content and supports the diagnosis of melanoma.
Prominently hypervascular enhancing mass with polypoid or eccentric wall thickening in the arterial phase. The tumor shows intense neovascularization and enhancement may be heterogeneous — areas of necrosis and hemorrhage are seen as non-enhancing regions. Luminal obstruction of variable degree may be present. Periesophageal fat invasion and regional lymphadenopathy are common.
Report Sentence
A prominently hypervascular enhancing, heterogeneous, polypoid mass is seen in the esophagus in the arterial phase; melanoma should be considered as the leading diagnosis in the presence of periesophageal invasion and regional lymphadenopathy.
On PET-CT, the primary esophageal mass shows intense FDG uptake (SUVmax usually >10). Melanoma is a tumor with high metabolic activity and FDG avidity is characteristic. PET-CT is also the most sensitive modality for detection of distant metastases (liver, lung, brain, bone, adrenal). Regional and distant lymph node involvement is detected with high sensitivity on PET-CT.
Report Sentence
The esophageal mass shows intense FDG uptake on PET-CT (SUVmax: ...); high metabolic activity is consistent with melanoma and distant metastasis evaluation should be performed.
On non-contrast CT, the esophageal mass may appear at soft tissue density or slightly higher density. Melanin accumulation may contribute to mildly increased density but is not a specific CT finding. Foci of intralesional hemorrhage may be seen as hyperdense areas. Calcification is rare.
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Non-contrast CT shows a soft tissue density mass in the esophagus; focal hyperdense areas may be consistent with hemorrhage.
Marked diffusion restriction and low ADC values on DWI reflect the high cellularity of the tumor and restricted water movement due to dense melanin accumulation. Diffusion restriction is prominent in both melanotic and amelanotic variants, supporting the malignant nature of the tumor.
Report Sentence
The mass shows marked diffusion restriction on DWI with low ADC values consistent with high cellularity; finding consistent with malignant melanoma.
On EUS, a heterogeneous hypoechoic, irregularly marginated mass invading mucosal and submucosal layers. Muscularis propria invasion and transmural spread are frequently seen. Periesophageal lymph nodes may show suspicious morphology. EUS is valuable for local tumor staging (T stage) and regional lymph node assessment.
Report Sentence
EUS demonstrates a heterogeneous hypoechoic, irregularly marginated mass invading the esophageal wall layers; accompanied by suspicious periesophageal lymph nodes.
Criteria
Most common type (70-90%). Prominent melanin production. Dark brown-black color on endoscopy. Typical T1 hyperintense + T2 hypointense signal on MRI. HMB-45, Melan-A, S-100 positive.
Distinct Features
Pathognomonic signal pattern on MRI (bright T1 + dark T2), intense FDG uptake on PET-CT, hypervascular enhancement on CT. Diagnosis is usually strongly guided by MRI findings.
Criteria
10-30% of all cases. Minimal or no melanin production. Pink-red color on endoscopy (can be confused with SCC or adenocarcinoma). Typical melanoma signal pattern not seen on MRI (T1 isointense/hypointense).
Distinct Features
No T1 hyperintensity on MRI — diagnosis is made by immunohistochemistry (HMB-45, Melan-A). CT and PET-CT findings are similar to melanotic type. More difficult to diagnose, carries risk of delayed diagnosis.
Criteria
Type showing polypoid growth into the lumen. May be associated with better prognosis because it causes early symptoms (dysphagia). Diagnosis can be made by endoscopic biopsy.
Distinct Features
Intraluminal polypoid mass on CT; filling defect on barium study; polypoid mass arising from mucosal layer on EUS.
Criteria
Type showing diffuse thickening of the esophageal wall. More aggressive course and poor prognosis. May show a linitis plastica-like appearance.
Distinct Features
Diffuse wall thickening on CT; stricture and luminal obstruction; difficult to distinguish from SCC, requires immunohistochemistry.
Distinguishing Feature
SCC does not show T1 hyperintense signal (isointense/hypointense); melanotic melanoma is markedly T1 hyperintense and T2 hypointense. SCC may not be distinguishable from amelanotic melanoma by MRI — immunohistochemistry is required.
Distinguishing Feature
GIST does not show T1 hyperintense signal, is usually T2 hyperintense and of submucosal/intramural origin; melanoma is of mucosal origin and shows characteristic T1 bright + T2 dark signal pattern in melanotic form.
Distinguishing Feature
Adenocarcinoma develops in the distal esophagus/GEJ on the background of Barrett esophagus, does not show T1 hyperintensity; melanotic melanoma shows pathognomonic T1 bright signal. Adenocarcinoma may be T2 hyperintense in mucinous component.
Distinguishing Feature
Leiomyosarcoma arises from muscularis propria, grows more slowly and does not show melanin signal; melanoma is of mucosal origin, grows rapidly and shows characteristic MR signal in melanotic form.
Urgency
emergentManagement
surgicalBiopsy
NeededFollow-up
3-monthPrimary esophageal melanoma is an extremely aggressive tumor requiring urgent multidisciplinary evaluation. Metastases are present in 40-80% of patients at diagnosis. Wide surgical resection (esophagectomy + lymphadenectomy) is the mainstay of treatment, but curative surgery is only possible in early-stage disease. Targeted therapy (dabrafenib + trametinib) may be applied in BRAF V600E mutation-positive cases. Immunotherapy (nivolumab, pembrolizumab) shows promising results in metastatic disease. Five-year survival is below 5% and prognosis is very poor. Follow-up with PET-CT at 3-month intervals is recommended after treatment.
Prognosis of primary esophageal melanoma is very poor (5-year survival <5%). Surgical resection can be performed with curative intent, but most cases have metastasis at diagnosis. Immunotherapy (anti-PD-1, anti-CTLA-4) is used in advanced stages.