Peritoneal “melanosis”

Abstract

A case of a 23 year old female with peritoneal melanosis associated with adenocarcinoma of the rectum is reported. During laparoscopic anterior resection of the rectum, diffuse black pigmentations on the parietal peritoneum, greater omentum, mesenteric lymph nodes and ovaries were discovered. The histopathological findings revealed the presence of macrophages packed with black pigment. These results together with clinical data excluded metastatic melanoma and confirmed the diagnosis of the rare condition called peritoneal melanosis. Due to the benign character of the lesions the laparoscopic treatment was continued. There were no remissions or progression of the peritoneal lesions observed. There have only been 14 cases of peritoneal melanosis reported in English literature and this is the second case of peritoneal melanosis that has been associated with adenocarcinoma of the large intestine.

Melanosis Peritonei Associated With Adenocarcinoma of the Sigmoid Colon

“…To our knowledge, only 17 cases of melanosis peritonei have been reported in the English literature to date [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. It is almost exclusively associated with other conditions: six with ovarian cystic teratomas [1][2][3][4][5][6], two with enteric duplication [7,8], one with gastric triplication [11], one with peritoneal cyst [10], one with serous cystadenoma of the ovary [9], one with mucinous cystadenoma of the ovary and adenocarcinoma in the colon [12], one with adenocarcinoma of the rectum [13], one with Peutz-Jeghers syndrome [14], and three with metastatic melanoma [15][16][17].…”

“…The pathogenesis of this condition is still unclear [13]. One theory, which was linked to ovarian teratoma, stated that the melanin pigment was produced inside the ovarian teratoma and spilled into the peritoneum following rupture of the cystic ovarian lesion [2][3][4]6,10].…”

“…Microscopically, the neoplastic nature of the lesion can be readily identified in haematoxylin and eosinstained sections [13]. Therefore, all cases with melanosis peritonei should have complete dermal and ophthalmologic examination to rule out metastatic spread of malignant melanoma [15].…”

“…Peritoneal melanosis commonly affects females from 18 to 28 years of age, with only one male case reported [ 13 ]. It also has been reported in the elderly but always in association with malignancy.…”

“…Previously reported cases have been associated with other conditions including mature ovarian cystic teratomas [ 1 - 6 ], an enteric duplication cyst [ 7 , 8 ], an ovarian serous cystadenoma [ 9 ], a peritoneal cyst [ 10 ], and gastric triplication [ 11 ]. Only two reported cases to date were associated with adenocarcinoma of the colon [ 12 , 13 ]. In this report, we present a case of peritoneal melanosis in an adult male previously diagnosed with adenocarcinoma of the sigmoid colon.…”