The first case of
primary melanoma of the gallbladder mucosa was described by Wieting
and Hambi, in 1907.
Both primary and
metastatic melanoma of the gallbladder are rare.
Both primary melanoma
and metastatic melanomas of the gallbladder have similar
presentations. Most patients are asymptomatic and lesions are
identified incidentally. Other presentations are those which, mimic
acute cholecystitis such as right upper quadrant or epigastric pain
and nausea or vomiting. Obstruction of the cystic duct by the tumor in
the absence of cholelithiasis can lead to obstructive jaundice.
malignant melanoma of the gall bladder is difficult or impossible to
distinguish from secondary melanoma.
Mac Fadden et al, compared primary
and metastatic biliary melanomas. To help in the differentiation
between primary and secondary malignant melanoma in the gall bladder,
it was suggested that certain criteria
should be fulfilled before primary melanoma is diagnosed.
(i) Tumours must
be solitary and arise from the mucosal surface of the gall bladder;
(ii) they must
either be papillary or polypoid;
(iii) they must
either display junctional activity or have any other primary sites
excluded by history taking, examination, and investigation.
examination reveal mostly spindle cells with vesicular nuclei and
Many cells stained positively for S 100 protein and HMB 45 using immunohistochemistry and they contained dark brown
pigment that stained as melanin pigment with Fontana-Masson.
The tumour may
metastasize to the common bile duct, stomach, the duodenum, the
jejunum, the lung, the brain and a bronchopulmonary lymph node.
In case of
metastic melanoma of gallbladder,
potential primary sites include skin,
oral cavity, anorectal region, uveal tract, and meninges.
Because of its rarity,
melanoma of the gallbladder should always be suspected in a patient
with a past history of cutaneous malignant melanoma who presents with
hepatobiliary symptoms. The prognosis of both primary and metastatic
disease is very poor.