peritoneal melanosis

Definition : Diffuse black pigmentation of the peritoneum. Peritoneal melanosis is a diffuse, black pigmentation of the peritoneum. It is a very rare condition characterized by melanin pigment deposition in the peritoneum.

The histopathological findings revealed the presence of macrophages packed with black pigment.

India-ink-colored (black) pigmentation is seen in the peritoneum, in the omentum, and on the surface of the ovary.

Biopsies of the omentum and peritoneum showed pigment in the stroma and pigment-laden histiocytic aggregation. An ultrastructural study found melanosome in the cytoplasm of the histiocytes.

These results together with clinical data excluded metastatic melanoma and confirmed the diagnosis of the race condition called peritoneal melanosis.

Due to the begin character of the lesions the laparoscopic treatment was continued.

There were no remissions or progression of the reported in English literature.

Associations

 malignant melanoma

• Peritoneal melanosis has been associated with metastatic melanoma involving the spleen (25700306) or the omentum (22437742).

 ovarian serous cystadenoma (12685549)

• Benign peritoneal melanosis is extremely rare and traditionally occurs in association with ovarian dermoid cysts, but rarely with peritoneal cyst, enteric duplication cyst or gastric triplication.
• Ovarian serous cystadenoma has not been previously described as a combined lesion of peritoneal melanosis.
• Based on the extremely rare incidence of this lesion and heterogeneous combined lesions, the possibility of an incidentally found, coexisting lesion couldn’t be excluded.
• However, peritoneal mesothelial cells pinched off during the developmental period might be a source of pigment-producing cells.

 melanotic peritoneal cyst (2334252)

 wall of the mucinous cystadenoma of the ovary (20173496)

 ruptured ovarian dermoid cyst (6724791)

• The ultrastructure of the omental and peritoneal pigmented nodules confirmed that the lesions consisted of histiocytes phagocytizing massive melanin pigments.
• Although no melanocytic neoplasm was found in the ovarian cystic teratoma, circumstance suggests that the ovarian, omental, and peritoneal pigmented lesions were secondary reactions to melanin released from the ruptured cystic teratoma.

 adenocarcinoma of the large intestine. (26619112)

Also :

 gastric triplication doi : 10.1016/S0022-3468(97)90532-7
 enteric duplication cyst

Open references

 Peritoneal "melanosis". Chang ES, Bachul P, Szura M, Szpor J, Okoń K, Walocha JA. Pol J Pathol. 2015 Sep;66(3):330-3. PMID: 26619112 Free

 Malignant ovarian melanoma with extensive pelvic and peritoneal metastasis: a case report and literature review. Gao R, Liu NF, Sheng XG. Chin J Cancer. 2010 Apr;29(4):460-2. PMID: 20346227.

Paywall references

 Peritoneal melanosis associated with mucinous cystadenoma of the ovary and adenocarcinoma of the colon. Kim SS, Nam JH, Kim SM, Choi YD, Lee JH. Int J Gynecol Pathol. 2010 Mar;29(2):113-6. doi : 10.1097/PGP.0b013e3181bb4182 PMID: 20173496