Annular pigmented actinic keratosis mimicking lentigo maligna melanoma in a 75-year-old female: An unusual presentation

Pigmented actinic keratosis (PAK) is an uncommon variant of actinic keratosis that can mimic different pigmented lesions, which may be benign or malignant. The diagnosis of PAK is often challenging because of overlapping features with lentigo maligna melanoma (LMM). Clinically, lesions of both conditions almost look similar; the diagnoses must be established histologically and with the help of immunostaining whenever needed. The distinction between a large PAK and LMM is important because their prognosis and management differ. We present a 75-year-old female with annular brown-to-black-colored maculo-plaque on forehead having clinical suspicious of melanocytic malignancy; which was diagnosed with a PAK on biopsy with help of histopathology and confirmed with Melan A/MART‑1 immunostaining.

Expression of MART-1 in human uveal melanoma cell lines / 中华眼底病杂志

Objective To observe the expression and transcription of MART-1 in human uveal melanoma cell lines 92-1,92-2,Ocm3,Me1285,as well as the possible effect ofmethylation on its expression.Methods The cell lines 92-1,92-2,Ocm3 and Me1285 were cultured routinely and tested for MART-1 expression at protein and mRNA level by FACS analysis,Western blot and RT-PCR respectively.Methylation status of the MART-1 promoter region in all the cell lines were checked by Southern blots of DNA digested with methylation sensitive restriction enzymes.Results As observed in FACS analysis and Western blot,92-1,92-2 and Ocm3 were MART-1 positive cell lines while Me1285 was negative cell line.Consistent with protein analysis,92-1 and Ocm3 cell lines showed MART-1 specific PCR products and there was no product in Me1285 cell line in RT-PCR.The MART-1 positive cell lines,92-1,92-2,and Ocm3 show methylation at the MspⅠ/Hpa Ⅱ site,and the Nru Ⅰ sites of all positive cell lines are not methylated.The MART-1 negative cell line Me1285 shows hyperrnethylation at the Nru Ⅰ site and the Msp Ⅰ/Hpa Ⅱ site is not methylated.Conclusions MART-1 could be expressed in human uveal melanoma cell lines 92-1,92-2 and Ocm3.The change of methylation status of MART-1 promoter may correlate with the transcription of MART-1.

Perivascular Epithelioid Cell Tumor in the Stomach

Perivascular epithelioid cell tumors or PEComas can arise in any location in the body. However, a limited number of cases of gastric PEComa have been reported. We present two cases of gastric PEComas. The first case involved a 62-year-old woman who presented with a 4.2 cm gastric subepithelial mass in the prepyloric antrum, and the second case involved a 67-year-old man with a 5.0 cm mass slightly below the gastroesophageal junction. Microscopic examination revealed that both tumors were composed of perivascular epithelioid cells that were immunoreactive for melanocytic and smooth muscle markers. Prior to surgery, the clinical impression of both tumors was gastrointestinal stromal tumor (GIST), and the second case was erroneously diagnosed as GIST even after microscopic examination. Although gastric PEComa is a very rare neoplasm, it should be considered in the differential diagnosis of gastric submucosal lesions.

Report of two cases of vacuolar interface dermatitis initially suspected as melanoma in situ and review of the literature / Relato de dois casos de dermatite de interface vacuolar, inicialmente diagnosticados como melanoma in situ, e revisão da literatura

ABSTRACT The diagnosis of melanocytic lesions can be challenging and immunohistochemical study is a valuable tool for dermatopathologists. We report two cases initially simulating melanoma in situ, reviewing the histopathological and immunohistochemical findings and the cases published in the literature with similar findings/results. We emphasize the importance of clinicopathological correlation in the evaluation of lesions with interface changes and in the "pseudomelanocytic nests", which may simulate melanoma in situ. We also highlight the importance of using a immunohistochemistry panel in addition to Melan-A, in the study of these lesions.

RESUMO O diagnóstico de lesões melanocíticas pode ser desafiador, e o estudo imuno-histoquímico é uma ferramenta valiosa para os dermatopatologistas. Relatamos dois casos inicialmente diagnosticados como melanoma in situ, avaliando os achados histopatológicos e imuno-histoquímicos e os casos publicados na literatura com resultados semelhantes. Ressaltamos a importância da correlação clinicopatológica na avaliação das lesões com danos na interface e nos "ninhos pseudomelanocíticos", que podem simular melanoma in situ. Destacamos também a importância da utilização de um painel de imuno-histoquímica, além do Melan-A, no estudo dessas lesões.

Inhibitory effect of live-attenuated Listeria monocytogenes-based vaccines carrying MART-1 gene on mouse malignant melanoma / 中华皮肤科杂志

Objective To investigate the inhibitory effect of live-attenuated Listeria monocytogenes (LM)-based vaccines expressing the gene encoding a melanoma differentiation antigen,MART-1,on malignant melanoma and their mechanism.Methods The constructed plasmid pERL3-MART-1 was used to transform live-attenuated LM by electroporation to construct recombinant LM.i.e.△inlB LM-MART-1 and △actA/△inlB LM-MART-1.The half lethal dose (LD50) of attenuated listeria strains was determined by concentration gradient dilution method.C57BL/6 mice were randomly divided into three groups,namely PBS group,△inlB LM-MART-1 group and △actA/△inlB LM-MART-1 group.Mice were inoculated by intraperitoneal injection of O.1 LD50 of each rLM strain or PBS only.One week later,the mice were injected subcutaneously with 1×105 B16F10 cells(a mouse melanoma cell strain)in 200μl of PBS.Reimmunization was performed on day 14 and 21.Subsequently,the growth of tumor and survival of tumor bearing mice were observed.All mice were killed on day 28,and tumor tissue as well as splenocytes were obtained from these mice for the detection of MART-1 gene expression by real-time quantitative PCR and the percentage of CD4+CD25+T cell by flow cytometry.Results The recombinant △inlB LM-MART-1 and △actA/△inlB LM-MART-1 were constructed successfully.The LD50 of △inlB LM and △actA/△inlB LM was lower than LM-EGDe by 100 and 10 000 times respectively.Compared with PBS,the tumor growth was inhibited with △inlB LM-MART-1 by 46.95%(F=6.3,P<0.05),and by 83.96% with △actA/△inlB LM-MART-1(F=37.8,P<0.01).The relative expression level of MART-1 in △inlB LM-MART-1 group and △actA/△inlB LM-MART-1 group was 8.988±0.207 and 11.315±0.445 times that in PBS group (both P<0.05).The percentage of CD4+CD25+T cells in splenocytes was (2.52±0.20)%,(1.14±0.13)% and (0.44±0.15)% in PBS group,△ialB LM-MART-1 group and △actA/△inlB LM-MART-1 group,respectively;the differences were statistically significant between the three groups (all P<O.01).Conclusions The attenuated LM carrying MART-1 gene has a lower virulence than LM reference strain,and could efficiently suppress the growth of melanoma and lengthen the survival of melanoma-beating mice.

The Expression of Melanin Pigment and Melanocytes in Basal Cell Carcinoma of Sun-Exposed and Non-Exposed Areas / 대한피부과학회지

BACKGROUND: Basal cell carcinomas (BCCs) are the most commonly encountered skin cancers. In Asian patients, marked pigmentation is frequently observed in BCC lesions. Although many authors have documented the incidence of pigmentation in BCCs, its pathogenesis, especially mechanisms associated with sun exposure, have rarely been studied. OBJECTIVE: This study aimed to evaluate the expression pattern of melanin pigments and melanocytes in BCCs of sun-exposed and non-exposed areas of skin and investigate the association of ultraviolet radiation with the pigmentation process of BCCs. METHODS: We examined 30 cases of BCCs occurring in sun-exposed areas of skin, and 8 cases of non-exposed areas of skin, using the Fontana-Masson and MART-1 immunohistochemical methods, with paraffin-embedded sections. RESULTS: Most melanin was found in tumor nests and surrounding dermal stroma (53.0%) and was superficially (60.0%) or fairly uniformly (33.3%) distributed in BCCs of sun-exposed areas. In all BCCs of sun-exposed areas, melanocytes were found in tumor nodules, not in dermal stroma. When the staining level of BCCs occurring in sun-exposed areas was compared with that of non-exposed areas, BCCs of sun-exposed areas showed significantly increased expression in Fontana-Masson (p<0.001, chi-square test) and MART-1 (7.75+/-4.77 vs 2.08+/-2.68; p=0.001, Mann-Whitney U-test) stains. CONCLUSION: Our immunohistochemical staining of BCC specimens revealed that ultraviolet radiation is closely associated with the pigmentation process of BCCs. Although accurate mechanisms are not yet established, these findings suggest a basis for the idea that complex phenomenon lead to hyperpigmentation in BCC.

The Expression of Melanin Pigment and Melanocytes in Basal Cell Carcinoma of Sun-Exposed and Non-Exposed Areas / 대한피부과학회지

BACKGROUND: Basal cell carcinomas (BCCs) are the most commonly encountered skin cancers. In Asian patients, marked pigmentation is frequently observed in BCC lesions. Although many authors have documented the incidence of pigmentation in BCCs, its pathogenesis, especially mechanisms associated with sun exposure, have rarely been studied. OBJECTIVE: This study aimed to evaluate the expression pattern of melanin pigments and melanocytes in BCCs of sun-exposed and non-exposed areas of skin and investigate the association of ultraviolet radiation with the pigmentation process of BCCs. METHODS: We examined 30 cases of BCCs occurring in sun-exposed areas of skin, and 8 cases of non-exposed areas of skin, using the Fontana-Masson and MART-1 immunohistochemical methods, with paraffin-embedded sections. RESULTS: Most melanin was found in tumor nests and surrounding dermal stroma (53.0%) and was superficially (60.0%) or fairly uniformly (33.3%) distributed in BCCs of sun-exposed areas. In all BCCs of sun-exposed areas, melanocytes were found in tumor nodules, not in dermal stroma. When the staining level of BCCs occurring in sun-exposed areas was compared with that of non-exposed areas, BCCs of sun-exposed areas showed significantly increased expression in Fontana-Masson (p<0.001, chi-square test) and MART-1 (7.75+/-4.77 vs 2.08+/-2.68; p=0.001, Mann-Whitney U-test) stains. CONCLUSION: Our immunohistochemical staining of BCC specimens revealed that ultraviolet radiation is closely associated with the pigmentation process of BCCs. Although accurate mechanisms are not yet established, these findings suggest a basis for the idea that complex phenomenon lead to hyperpigmentation in BCC.

Value of Histological Staining in Differential Diagnosis of Vitiligo / 대한피부과학회지

BACKGROUND: Vitiligo is a depigmented disorder, causing serious cosmetic problems for patients. In diagnostic and therapeutic aspects, vitiligo should be differentiated from other hypopigmented disorders as the therapeutic approach and prognosis are different for each disease. OBJECTIVE: This study aimed to compare the usefulness of several markers for melanocytes or melanin in differential diagnosis of vitiligo. METHODS: Twenty-eight patients were studied, who were diagnosed clinically as suffering from one of the following diseases: vitiligo, nevus depigmentosus, pityriasis alba, postinflammatory hypopigmentation, and idiopathic guttate hypomelanosis. Skin samples (frozen or paraffin-fixed) were obtained from depigmented patches and normal neighboring skin (control). Histological staining was performed by using Fontana-Masson, S-100, MART-1, and DOPA. The staining level of lesional skin was compared with that of normal skin. RESULTS: When the staining level of vitiligo was compared with that of others, vitiligo was significantly lower in Fontana-Masson (13.3+/-17.2% vs 44.4+/-23.7%), S-100 (49.5+/-14.9% vs 74.7+/-24.2%), MART-1 (7.4+/-8.7% vs 68+/-33.9%), and DOPA (9.5+/-11.3% vs 58.2+/-29.5%) (p<0.0001). CONCLUSION: MART-1 and DOPA are valuable markers in differential diagnosis of vitiligo. However, Fontana-Masson, a marker of melanin, had some limits in detecting melanocytes, and S-100 showed non-specific staining other than melanocytes.

MART-1 Expression in Malignant Melanoma and Benign Melanocytic Nevi / 대한피부과학회지

BACKGROUND: MART-1(melanoma antigen recognized by T cell) is a well-known marker for malignant melanoma. Its immunoreactivity is also expressed in other melanocytic lineage. OBJECTIVE: Our purpose is to evaluate the usefulness of MART-1 in the diagnosis of malignant melanoma. METHODS: MART-1 immunostaining was performed in 26 cases of malignant melanoma and 12 cases of benign melanocytic nevi. HMB-45 immunostaining was performed in 26 cases of malignant melanoma. RESULTS: 1. Eighteen of 26 melanomas(69%) and 10 of 12 benign melanocytic nevi(83%) showed reactivity with MART-1. 2. HMB-45 showed a higher sensitivity(85%) than that of MART-1 in the staining of malignant melanoma. 3. Two of 5 HMB-45-negative melanomas were immunoreactive with MART-1, and 2 of 7 MART-1-negative melanomas were reactive with HMB-45. CONCLUSION:MART-1 immunostaining is not helpful to differentiate malignant melanoma from benign melanocytic nevi. MART-1 was immunoreactive to some cases of HMB-45 negative malignant melanoma. MART-1, together with S-100 protein and HMB-45, is another useful marker of malignant melanoma.