Deposition Of Melanin Pigment Research Articles

Collision Cutaneous Neoplasms Consisting of Melanoma and Basal Cell Carcinoma.

Collision tumors are defined as two histologically different tumor types that arise at the same anatomical location. According to the literature review performed, there are reports of 27 cases of collision tumors involving lentigo maligna melanoma (LMM) in-situ and basal cell carcinoma (BCC). In the absence of melanocytic extension beyond the lamina propria of the BCC compartment, mixed tumors are considered as melanoma in-situ colonizing the BCC, rather than invasive melanomas. We report an uncommon case of collision of BCC with LMM, two primary skin tumors that are seen in patients with significant sunlight exposure. In our case, the patient is a 91-year-old male presented with a translucent plaque with areas of brown pigmentation on his left lateral canthus. He had a history of multiple BCCs, squamous cell carcinomas and an invasive melanoma of right cheek. Given the clinical impression of BCC, the lesion was curetted. Histological examination demonstrated melanoma in-situ heavily infiltrating the dermal nodules of BCC. Deposits of melanin pigment were scattered throughout the tumor. The BCC contained about 50% atypical melanocytes. Further immunohistochemical evaluation with melanocytic and epithelial markers (melanin A, SOX-10, pan-cytokeratin and p63) confirmed the diagnosis. An unequivocal independent invasive melanoma component was not identified in this material. The collision of BCC and LMM is very rare. However, given the sun-damaged changes promote both tumors, their development at the same site, although unexpected, can be explained. Since the prognosis of the two entities is independent, wider excision to exclude invasive malignant melanoma is indicated.

Clinical evaluation of platelet-rich fibrin membrane in the gingival depigmentation procedure: A case report

Gingival pigmentation, which is caused by the deposition of melanin pigment, may not be a medical problem but is still a primary esthetic concern for many people. Esthetic gingival depigmentation performed in such patients leads to excellent results. The platelet concentrate, which is often addressed as a windfall in the regenerative therapy in periodontology, accelerates wound healing by excellent neovascularisation. It also promotes fast cicatricle tissue remodeling. This case report highlights the effectiveness of Platelet-rich fibrin (PRF) membrane in the depigmentation procedure. Keywords: Gingival Depigmentation, Esthetics, Platelet-rich fibrin.

Investigating the cell and developmental biology of plant infection by the rice blast fungus Magnaporthe oryzae

Magnaporthe oryzae is the causal agent of rice blast disease, the most widespread and serious disease of cultivated rice. Live cell imaging and quantitative 4D image analysis have provided new insight into the mechanisms by which the fungus infects host cells and spreads rapidly in plant tissue. In this video review article, we apply live cell imaging approaches to understanding the cell and developmental biology of rice blast disease. To gain entry to host plants, M. oryzae develops a specialised infection structure called an appressorium, a unicellular dome-shaped cell which generates enormous turgor, translated into mechanical force to rupture the leaf cuticle. Appressorium development is induced by perception of the hydrophobic leaf surface and nutrient deprivation. Cargo-independent autophagy in the three-celled conidium, controlled by cell cycle regulation, is essential for appressorium morphogenesis. Appressorium maturation involves turgor generation and melanin pigment deposition in the appressorial cell wall. Once a threshold of turgor has been reached, this triggers re-polarisation which requires regulated generation of reactive oxygen species, to facilitate septin GTPase-dependent cytoskeletal re-organisation and re-polarisation of the appressorium to form a narrow, rigid penetration peg. Infection of host tissue requires a further morphogenetic transition to a pseudohyphal-type of growth within colonised rice cells. At the same time the fungus secretes an arsenal of effector proteins to suppress plant immunity. Many effectors are secreted into host cells directly, which involves a specific secretory pathway and a specialised structure called the biotrophic interfacial complex. Cell-to-cell spread of the fungus then requires development of a specialised structure, the transpressorium, that is used to traverse pit field sites, allowing the fungus to maintain host cell membrane integrity as new living plant cells are invaded. Thereafter, the fungus rapidly moves through plant tissue and host cells begin to die, as the fungus switches to necrotrophic growth and disease symptoms develop. These morphogenetic transitions are reviewed in the context of live cell imaging studies.

Gingival Depigmentation

Gingival hyperpigmentation is the condition where melanin deposition occurs in the suprabasal cell layers of the gingival epithelium. Gingival hyperpigmentation is a multifactorial benign condition which causes esthetic concern to the person. Melanin is a nonhemoglobin-derived pigment formed by melanocytes, which are dendritic cells of neuroectodermal origin in the basal and spinous layers. Melanin is a brown-colored pigment, and it is the result of endogenous pigmentation. The deposition of melanin pigment darkens the color of the gingiva. Many individuals visit the dentist or periodontist to seek the treatment of hyperpigmentation of the gingiva. Gingival pigmentation is usually considered as a genetic factor and affects different races differently. Various treatment modalities are available to remove gingival hyperpigmentation which includes scalpel technique, abrasion using diamond bur, laser therapy, electrosurgery, cryotherapy, chemical cauterization, depigmentation followed by gingival autografts, or platelet-rich fibrin. The present case report describes the case of gingival hyperpigmentation managed by scalpel technique and abrasions by diamond bur which is a simple and a cost-effective technique with satisfactory results.

Impeding Minocycline Induced Hyperpigmentation by Pomegranate Extracting the Epidermis of Guinea Pig

Objective: This study was planned over the hypothesis that pomegranate extract rich in ellagic acid used with minocycline could decrease its adverse effect and prolong its therapeutic use and efficacy. Study design and Setting: This experimental study was done in the department of anatomy, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Center, Karachi, Methodology: We acquired 40 guinea pigs (male, adult, 450 – 550 gm), randomly divided them into 4 groups.Group B received 0.0003mg/g bodyweight of minocycline only, group C was given 0.0003mg/g bodyweight of minocycline with 0.4mg/g bodyweight of pomegranate, group D was given 0.4mg/g bodyweight pomegranate only; with keeping group A with no intervention at laboratory diet for 8 weeks. After the experimental period, the animals were sacrificed, H & E and DOPA-OXIDASE staining was done on harvested skin tissues for morphometric observations under light microscopy. Results: The results showed that minocycline induced reduction in mean thickness of epidermis and increased melanin pigment deposition. Mean number of melanocytes decreased with pomegranate use though the difference was insignificant (P-value > 0.05) but consistent and measurable. Conclusions: It was proven that by including pomegranate in our daily diet, the process of hyperpigmentation of skin induced by the broad spectrum tetracycline particularly minocycline, can be slow down by decreasing the activity of tyrosinase enzyme, thus it provides a novel pathway to fight against any other drug induced hyperpigmentation occurring due to increase activity of tyrosinase enzyme

A case of perivascular epithelioid cell tumor with marked melanin pigment deposition arising from the retroperitoneum

A case of perivascular epithelioid cell tumor with marked melanin pigment deposition arising from the retroperitoneum

Expression of glucocorticoid and mineralocorticoid receptor genes co-varies with a stress-related colour signal in barn owls

Glucocorticoid hormones are important intermediates between an organism and its environment. They enable an organism to adjust its behavioural and physiological processes in response to environmental changes by binding to mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) expressed in many tissues, including the integument. The regulation of glucocorticoids co-varies with melanin-based colouration in numerous species, an association that might result from pleiotropic effects of genes in the melanocortin system and evolve within a signalling context. Most studies have focused on the circulating levels of glucocorticoids disregarding the receptors that mediate their action, and that might partly account for the covariation between the regulation of stress and melanin-based colouration. We investigated the association of the expression levels of GR and MR genes with melanin-based colouration in the growing feathers of nestling barn owls (Tyto alba). We also explored the association between GR and MR expression levels and the expression of genes related to the melanocortin system and melanogenesis to better understand the origin of the link between the expression of receptors to which corticosterone binds and melanin-based colouration. Nestling barn owls displaying larger eumelanic black feather spots expressed GR and MR at lower levels than smaller-spotted individuals. However, we found that the expression of the GR and MR genes was positively rather than negatively correlated with the expression of genes involved in the deposition of melanin pigments at the time we sampled the nestlings. This provides mixed evidence of the association between melanin-based traits and MR and GR gene expression. The finding that the expression of GR and MR was positively associated with the expression of the PCSK2 gene (encoding one of the protein convertase responsible for the production of hormone peptide ACTH and α-MSH) suggests that the melanocortin system may be implicated in the establishment of the covariation between melanin-based colour and the expression of receptors to which glucocorticoids bind. However, further studies investigating the expression of melanin-based traits with stress-related endpoints at different time points of feather development will be necessary to understand better the proximate mechanism linking melanin-based traits with stress.

A review of Gloger's rule, an ecogeographical rule of colour: definitions, interpretations and evidence

Gloger's rule is an ecogeographical rule that links animal colouration with climatic variation. This rule is named after C.W.L. Gloger who was one of the first to summarise the associations between climatic variation and animal colouration, noting in particular that birds and mammals seemed more pigmented in tropical regions. The term 'Gloger's rule' was coined by B. Rensch in 1929 and included different patterns of variation from those described by Gloger. Rensch defined the rule in two ways: a simple version stating that endothermic animals are predicted to be darker in warmer and humid areas due to the increased deposition of melanin pigments; and a complex version that includes the differential effects of humidity and temperature on both main types of melanin pigments-eu- and phaeo-melanin. The blackish eu-melanins are predicted to increase with humidity, and decrease only at extreme low temperatures, while the brown-yellowish phaeomelanins prevail in dry and warm regions and decrease rapidly with lower temperatures. A survey of the literature indicates that there is considerable variation/confusion in the way Gloger's rule is understood (based on 271 studies that define the rule). Whereas the complex version is hardly mentioned, only a quarter of the definitions are consistent with the simple version of Gloger's rule (darker where warm and wet), and most definitions mention only the effects of humidity (darker where wet). A smaller subset of studies define the rule based on other correlated climatic and environmental variables such as vegetation, latitude, altitude, solar radiation, etc., and a few even contradict the original definition (darker where cold). Based on the literature survey, I synthesised the qualitative (N=124 studies) and quantitative (meta-analytically, N=38 studies, 241 effects) evidence testing the simple version of Gloger's rule (I found no tests of the complex version). Both lines of evidence supported the predicted effects of humidity (and closely linked variables) on colour variation, but not the effects of temperature. Moreover, humidity effects are not restricted to birds and mammals, as the data indicate that these effects also apply to insects. This suggests that the simple version of Gloger's rule as originally defined may not be valid, and possibly that the rule should be re-formulated in terms of humidity effects only. I suggest, however, that more data are needed before such a reformulation, due to potential publication biases. In conclusion, I recommend that authors cite Rensch when referring to Gloger's rule and that they make clear which version they are referring to. Future research should concentrate on rigorously testing the validity and generality of both versions of Gloger's rule and establishing the mechanism(s) responsible for the patterns it describes. Since humidity seems to be the core climatic variable behind Gloger's rule, I suggest that the two most plausible mechanisms are camouflage and protection against parasites/pathogens, the latter possibly through pleiotropic effects on the immune system. Understanding the processes that lead to climatic effects on animal colouration may provide insights into past and future patterns of adaptation to climatic change.

A Comparison of 940 nm Diode Laser and Cryosurgery With Liquid Nitrogen in the Treatment of Gingival Physiologic Hyperpigmentation Using Split Mouth Technique: 12 Months Follow Up.

Introduction: Gingival hyperpigmentation is excessive deposition of melanin pigments in the epithelium of gingiva which affects facial esthetics. Various surgical methods for gingival depigmentation have been used to treat the darkened color of pigmented gingiva. This study compared the use of 940 nm diode laser and liquid nitrogen cryosurgery in the treatment of gingival physiologic hyperpigmentation in terms of gingival depigmentation, postoperative pain, healing duration, pigmentation recurrence, and patients' satisfaction. Methods: Fifteen systemically healthy patients (11 females and 4 males; 17-35 years of age) with bilateral gingival physiologic hyperpigmentation were enrolled in this split-mouth randomized study. Maxillary anterior labial gingiva of each patient was divided into left and right halves, and each half was randomly depigmented by either laser or cryosurgery. Patients were given questionnaires to evaluate the procedures and were followed up in 3, 7, 10, 17 and 21 days postoperatively for the assessment of gingival healing and 1, 3, 6 and 12 months after the treatments to detect any sign of pigmentation recurrence. Results: The severity of post-op pain measured by visual analogue scale (VAS) was mild to average and showed no significant difference between the 2 modalities (P>0.05). There was no considerable swelling or hemorrhage after the treatment procedures and the healing duration was significantly shorter in laser (P<0.05). The degree of pigmentation in all gingival sites treated by laser reached and remained at zero until the last follow up (1 year) and reached zero in 9 out of 15 cryosurgerytreated sites. All patients were completely satisfied with the laser, and 9 out of 15 were completely satisfied with cryosurgery. No pigmentation recurrence was observed during any follow-up periods. Conclusion: Removal of gingival physiologic hyperpigmentation by laser therapy and cryotherapy was effective and safe. The efficiency of the laser was better than cryotherapy.

Primary Malignant Melanoma of Brainstem Medulla Mimicking as Cavernoma – Case Report

Aim of this case report is to present a rare case of primary malignant melanoma of brain stem at the region of medulla oblongata mimicking as cavernoma. 40-year-old male presented with vertigo, headache, dizziness for 1 month. MRI showed pear shaped T1 hyperintense lesion at medulla oblongata and predominantly hypointense on T2 with focal area of hemorrhage. Lesion showed diffuse enhancement on postcontrast images. On plain CT lesion was Hyperdense. It was initially reported as Cavernoma. Surgical excision of lesion was done with per-op findings of solid, dark maroon colored lesion with hemorrhage. Histopathology showed neoplastic lesion with abundant melanin pigment deposition. The lesion was finally diagnosed as Malignant neoplasm with features favoring Malignant Melanoma.

Oral supplementation of L-glutathione prevents ultraviolet B-induced melanogenesis and oxidative stress in BALB/c mice.

Dietary antioxidant supplements such as L-glutathione have gained considerable attention in dermatology and cosmeceutical fields. L-glutathione possesses antiaging, antimelanogenic, antioxidant, and anticancer properties. This study aimed to investigate the inhibitory effects of L-glutathione on melanogenesis activity and oxidative stress in ultraviolet B (UVB)-irradiated BALB/c mice. Eighteen female BALB/c mice were randomly divided into 3 groups: a control group (n=6), a group without UVB irradiation and L-glutathione administration; a UVB irradiated group (n=6), a group irradiated with a UVB dose of 250 mJ/cm2 for 3 min; and a treatment group (n=6), a group irradiated with UVB and treated with 100 mg/kg of L-glutathione by oral gavage. Treatment was given for 14 days, and UVB irradiation was given on days 9, 11, and 13. Oral L-glutathione significantly (P<0.05) reduced lipid peroxidation and elevated superoxide dismutase activity the and glutathione level. L-glutathione also inhibited melanin content and tyrosinase activity significantly (P<0.05) as compared with the UVB-irradiated group. Histopathological examination also showed that L-glutathione reduced the deposition of melanin pigment in the basal layer of the epidermis as compared with that in UVB-irradiated mice. All in all, the present study demonstrated that L-glutathione has the potential to be developed as a photoprotection agent against UVB-induced oxidative stress and melanogenesis.

A recent shift in the pigmentation phenotype of a wild Neotropical primate

The colors of primates are among the most diverse phenotypes in mammals. These colors are mostly produced by the deposition of melanin pigments in hairs. Many species show considerable variability in pigmentation, but this is always temporarily fixed. Here we report the first rapid change in the pigmentation phenotype of a primate. In the last five years, the pelage of mantled howler monkeys Alouatta palliata inhabiting Costa Rica has started to change from fully black to yellowish, constituting a conspicuous color change. Raman spectroscopy analyses of hairs show that the change is due to a shift toward the production of the sulphurated form of melanin, termed pheomelanin. Most animals with anomalous coloration have been observed in forests surrounding intensive cultivations where sulfur-containing pesticides are frequently used. Exposure to environmental sulfur may increase the availability of sulfhydryls to cells, which may favor pheomelanin synthesis in melanocytes and explain the pigmentation shift.

Immune responses of Aedes togoi, Anopheles paraliae and Anopheles lesteri against nocturnally subperiodic Brugia malayi microfilariae during migration from the midgut to the site of development

BackgroundLymphatic filariasis is a mosquito-borne disease caused by filarioid nematodes. A comparative understanding of parasite biology and host-parasite interactions can provide information necessary for developing intervention programmes for vector control. Here, to understand such interactions, we choose highly susceptible filariasis vectors (Aedes togoi and Anopheles lesteri) as well as Anopheles paraliae, which has lower susceptibility, infected them with nocturnally subperiodic (NSP) Brugia malayi microfilariae (mf) and studied the exsheathment, migration and innate immune responses among them.MethodsMosquito-parasite relationships were systematically investigated from the time mf entered the midgut until they reached their development site in the thoracic musculature (12 time points).ResultsResults showed that exsheathment of B. malayi mf occurred in the midgut of all mosquito species and was completed within 24 h post-blood meal. The migration of B. malayi mf from the midgut to thoracic muscles of the highly susceptible mosquitoes Ae. togoi and An. lesteri was more rapid than in the low susceptibility mosquito, An. paraliae. Melanisation and degeneration, two distinct refractory phenotypes, of mf were found in the midgut, haemocoel and thoracic musculature of all mosquito species. Melanisation is a complex biochemical cascade that results in deposition of melanin pigment on a capsule around the worms. Also, some biological environments in the body are inhospitable to parasite development and cause direct toxicity that results in vacuolated or degenerated worms. Even though Ae. togoi is highly susceptible to B. malayi, melanisation responses against B. malayi mf were first noted in the haemocoel of Ae. togoi, followed by a degeneration process. In contrast, in An. lesteri and An. paraliae, the degeneration process occurred in the haemocoel and thoracic musculature prior to melanisation responses.ConclusionThis study provides a thorough description of the comparative pathobiology of responses of mosquitoes against the filarial worm B. malayi.

Rare Case of Malignant Melanoma of Lacrimal Sac

Presentation A 60 year old female presented to our clinic in July 2015 with complaints of left eye epiphora, and painless gradually increasing mass in the medial canthal area for 4 months. Probing revealed hard stop. At the time the mass was above the MCT and appeared separate from lacrimal sac. She was advised biopsy, but was lost to follow-up, only to present 6months later with a massive increase in the size of mass. There was no history of bloody discharge. On Examination, both eyes had senile cataract with BCVA of 6/24 in Right eye and absent light perception in left eye. A single, irregular, diffuse, firm mass was present in the medial canthal area of left eye, measuring approximately 2.5cmX2.5cm in size, with 3mm horizontal dystopia and blackish skin pigmentation. It involved the medial part of both upper and lower lid, lacrimal sac and canaliculi. It was non tender, immobile, with no surface ulcerations or pulsations. Excessive watering was present in the left eye, syringing could not be done since puncta were not visualized. There were no other swellings, no lymphadenopathy, and no history of significant weight loss. Hematological investigations were normal. Neuroimaging revealed a well-defined heterogenously enhancing solid lesion in the region of medial canthus of Left eye, about 2.3X2.8X1.7cm, involving the extraconal space, causing scalloping and widening of Left lacrimal fossa and NLD, and mild lateral displacement of the globe. Incisional biopsy showed tumor tissue composed of clusters of malignant cells-pleomorphic with high nuclear-cytoplasmic ratio, vesicular nuclei and prominent eosinophillic macronuclei. Foci of melanin pigment deposition were seen, leading to a diagnosis of malignant melanoma of the lacrimal sac. Metastatic work-up revealed lytic lesions in left frontal and right parietal skull bones and fibronodular opacities in upper and middle lobes of right lung, alongwith mediastinal lymphadenopathy. Hence the final staging was T4aN0M1c. No surgical treatment was planned and instead patient was referred for palliative systemic chemotherapy and radiotherapy. Discussion Malignant melanoma is a malignancy of the pigmentproducing melanocytes. It usually affects the skin and rarely

A Case of Primary Malignant Melanoma of the Esophagus

Primary malignant melanoma of the esophagus is a rare disease and aggressive tumor of the esophagus. Primary malignant melanoma represents 0.1% to 0.2% of all primary esophageal cancers. Hematogenous and lymphatic metastasis are common. The prognosis is quiet poor, so early dectection and accurate diagnosis should be made. We encountered a patient with a black esophageal lesion, which was histopathologically confirmed to be primary malignant melanoma of the esophagus. A 65-year-old men was admitted for evaluation of a black pigmentation at lower esophagus which was found at regular general physical exam. He had no symptoms, no history of any illness and no family history of cancer. Physical examination found no abnormal pigmentations of the skin or mucosa. Endoscopy revealed multiple scattered 0.4cm sized black pigmented ulcerative lesion at 37cm from the incisors (Figure 1). Pathological findings from endoscopy show melanin pigment deposition and melanophage infiltration (Figure 2). Immunohistochemical staining was positive for HMB45, Ki-67, S100 and melan-A. Computed tomography of chest and abdomen showed no evidence of discernible lesion in the stomach, lung and regional lymphadenopathy. Positron emission tomography demonstrated no regional or distant metastasis. He received esophagectomy and gastroesphagostomy. Muscularis mucosa was involved, but the surgical margin of the esophagus was free from tumors. And all regional lymph nodes were found free of tumor.Figure 1Figure 2

Melanotic Neuroectodermal Tumor of Infancy (MNTI) – A case report

MNTI is a rare dysembryogenic tumor of infancy. It is a benign neoplasm usually seen in the first 6 months of life. The predominant site of origin is the pre-maxilla with rapid expansile growth manifesting with feeding difficulty. The tumor arises from the neural crest cells. On histological examination, typical biphasic population of cells with deposits of melanin pigment is seen. Immunohistochemistry (IHC) study helps in confirming the diagnosis. It has a locally aggressive course with high recurrence rate. Malignant transformation and metastatic spread is extremely rare. Wide excision of the tumor is the treatment. Thorough follow-up is recommended for a period of 1 year. Early detection and proper surgery decreases complications with favourable outcome. A case report of this tumor affecting a 5-month old male child with involvement of the right maxillary antrum is being presented here. This case is reported for its rarity, and classical clinico-pathological findings.

Melanocytic Lesions of the Central Nervous System

Central nervous system (CNS) melanocytic lesions are relatively uncommon and range from benign primary pigmented CNS lesions to aggressive malignant neoplasms. Primary CNS neoplasms include diffuse leptomeningeal melanocytosis and melanomatosis, melanocytoma, and primary malignant melanoma. Other CNS neoplasms that may show melanin pigment deposition include melanotic schwannoma, melanocytic medulloblastoma, and rarely other neuroepithelial neoplasms. These lesions may be difficult to distinguish from metastatic malignant melanoma. Clinicopathological correlation is important in this distinction and is crucial in helping to determine the prognosis and management of patients with these tumors.

Aberraciones cromáticas en aves de la colección ornitológica del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”

Chromatic aberrations in birds of the ornithological collection of the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. The paper makes out a strong case for determine chromatic aberrations that affect the coloring of the birds in the ornithological collection of the Museo Argentino de Ciencias Naturales de Buenos Aires. These alterations are due to excess or deficiency in the production and/or deposition of melanin pigment, the affect families belong to Tinamidae, Spheniscidae, Ardeidae, Threskiornithidae, Anatidae, Falconidae, Rallidae, Charadriidae, Columbidae, Strigidae, Momotidae, Furnariidae, Mimidae, Motacillidae, Emberizidae and Icteridae. Within the proposed changes, the partial leucism (40,5 %) is the most numerous, followed by pastel dilution (23,8 %), albinism (14,3 %) and finally brown aberrations, ino and partial eumelanism, each one of then had (7,1 %).

Peritoneal Melanosis Associated With Mucinous Cystadenoma of the Ovary and Adenocarcinoma of the Colon

Peritoneal melanosis, a diffuse, black pigmentation of the peritoneum, is a very rare condition characterized by melanin pigment deposition in the peritoneum. In this paper, we describe a case of peritoneal melanosis associated with a mucinous cystadenoma on an ovary and adenocarcinoma in the colon of 68-year-old women. The patient was referred for an evaluation of lower abdominal pain and distension. Laboratory results showed anemia and elevated CA 125 levels. A pelvic computed tomographic scan revealed a huge multicystic mass on the right ovary and a well-enhancing intraluminal mass located at the rectosigmoid junction. During a surgical procedure, India-ink-colored (black) pigmentation was 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. Pigment was also present in the wall of the mucinous cystadenoma of the ovary and colonic serosa. An ultrastructural study found melanosome in the cytoplasm of the histiocytes.

A unique case of urinary bladder simple melanosis: a case report and review of the literature

Melanosis refers to abnormal or excessive deposition of melanin pigment in the cells and/or tissue, which can be seen in any organ but commonly in skin and oral mucosa. Melanosis of the urinary bladder is an extremely rare benign condition and only a handful of cases been reported in the English literature before. In this article, we report a new case of urinary melanosis, describe the differential diagnostic features from pseudomelanosis and offer clues for correct diagnosis. We also provide comprehensive review of the literature on the subject.