Melanoacanthoma is a rare benign mixed tumor of both keratinocytes and melanocytes. Although some authors said that it is a rare variant of seborrheic keratosis, it has clinical and histological features distinct from seborrheic keratosis. It has large dendritic melanin-laden melanocytes throughout all levels of epidermis showing a disruption of melanin transfer from the melanocytes to neighboring keratinocytes. However, it is difficult to distinguish melanocytes clearly from cutaneous pigment in immunohistochemical stain with usually used brown chromogen. We used chromogen with brick-red indicator product (VECTOR(R) NovaRED(TM)) in S-100 and melan-A immunohistochemical staining to distinguish melanocytes from melanin laden keratinocytes. We suggest that the immunohistochemical staining using this novel chromogen may be useful in the diagnosis of melanoacanthoma.
Epidermis ; Immunohistochemistry ; Keratinocytes ; Keratosis, Seborrheic ; MART-1 Antigen ; Melanins ; Melanocytes

BACKGROUND: Immunohistochemical confirmation is needed to correctly diagnose malignant melanoma, due to its heterogeneous histological appearance. OBJECTIVE: In the diagnosis of malignant melanoma, we evaluated the usefulness of recently introduced antibodies against Melan-A and tyrosinase, and compared them with antibodies against S100 protein and HMB-45. METHOD: Immunohistochemical staining with the above 4 antibodies was performed on 36 cases of malignant melanoma which had been excised. The percentage of positive tumor cells with the semi-quantitative estimation were than graded as follows; 0% = grade 0, 1-25% = grade 1, 26-50% = grade 2, 51-75% = grade 3, 76-100% = grade 4. We regarded grade 0 as negative, and grade 1 to 4 as positive. The association of Breslow thickness with the individual grade of 4 antibodies was then evaluated. RESULTS: 1. Positiveness of the 4 antibodies were as follows; 100% of the antibody against S100 protein, 97.2% of HMB-45, 97.2% of the antibody against tyrosinase, 91.7% of the antibody against Melan-A. 2. A case of a HMB-45 negative melanoma showed a grade 4 for the antibody against S100 protein, a grade 2 for the antibody against Melan-A, and a grade 3 for the antibody against tyrosinase. 3. The Breslow thickness had a significant positive correlation with the individual grade of antibody against Melan-A. CONCLUSION: In combination with the antibody against S100 protein and HMB-45, the newly developed antibodies against Melan-A and tyrosinase may be useful in the diagnosis of malignant melanoma.
Antibodies* ; Diagnosis ; MART-1 Antigen* ; Melanoma* ; Monophenol Monooxygenase*

BACKGROUND: Melanomas need to be differentiated from benign melanocytic lesions during diagnosis. However, it is difficult to differentiate them using histopathology alone, since both neoplasms have broad morphological spectrums and subtle differentiating features. OBJECTIVE: To evaluate the usefulness of Ki-67/Melan-A double staining for differentiating melanoma from benign melanocytic nevi. METHODS: We selected 20 cases of intradermal nevi, 20 cases of compound nevi, 5 cases of dysplastic nevi, and 25 cases of melanoma from clinicopathologically proven cases reviewed by the Department of Dermatology at our medical center. Ki-67/Melan-A double staining was performed, and the Melan-A verified Ki-67 index (Ki-67-M index) and Ki-67 index were measured. The immunopositivity was measured in the deepest third of the lesions. RESULTS: The Ki-67-M index of intradermal nevi, compound nevi, dysplastic nevi, and melanoma were 0.4+/-0.9%, 1.0+/-1.1%, 4.3+/-1.7%, and 24.1+/-10.9%, respectively. The best Ki-67/Melan-A cut-off point to distinguish melanomas from benign melanocytic nevi was 5%; the sensitivity and specificity were 100% and 97.7%, respectively. Immunopositivity in the deepest third of the intradermal nevi, compound nevi, and melanoma, were 10.5%, 20%, and 100%, respectively; the sensitivity and specificity for diagnosing melanoma were 100% and 84.6%, respectively. The sensitivity and specificity of combined Ki-67-M and immunopositivity in the deepest third for diagnosing melanoma were 100% and 97.7%, respectively. CONCLUSION: The Ki-67-M index and immunopositivity in the deepest third of melanoma were significantly higher than that of benign melanocytic nevi. Therefore, Ki-67/Melan-A double staining is a potentially valuable diagnostic tool for differentiating melanoma from benign melanocytic nevi.
Dermatology ; Diagnosis ; Dysplastic Nevus Syndrome ; MART-1 Antigen ; Melanoma* ; Nevus ; Nevus, Intradermal ; Nevus, Pigmented* ; Sensitivity and Specificity

Anti-melanogenic effects of amaranth (AT), one of the key source of squalene, were investigated in melanocytes. Amaranth seed powder was extracted with water and melan-a cells were treated with various concentrations of AT. By using HPLC, content of myo-inositol, one of potential active components, was measured in the crude extract of AT.AT reduced the melanin content in melan-a melanocytes and down-regulated melanogenic enzyme activity such as tyrosinase, TRP-1 and TRP-2. By regulating melanogenic enzyme activity, AT may be a potential natural source for whitening agent. Myo-inositol was detected in AT by HPLC and may be one of the active compounds from AT involved in the regulation of anti-melanogenesis. In this study, we demonstrated that AT has anti-melanogenesis properties. This new function of amaranth may be useful in the development of new skin-whitening products and its value as food.
Amaranthus* ; Chromatography, High Pressure Liquid ; MART-1 Antigen* ; Melanins* ; Melanocytes ; Monophenol Monooxygenase ; Squalene ; Water

To follow up the change of melanocytes to keratinocytes ratio in stratified epidermis reconstructed by mixed culture of these cells, the author investigated the ratio of melanocyte to keratinocyte in the basal layer of reconstructed epidermis after induction of stratification for 1 week with cocultured melanocyte and keratinocyte in various ratio. Initial mixing ratios of melanocyte to keratinocyte were 1 : 10, 1 : 20, 1 : 40, 1 : 80. Post ratios were changed to 1 : 6.7, 1 : 10.7, 1 : 12.6, 1 : 13.8 respectively after 1 week. Eight time of initial gap reduced to two times and melanocyte to keratinocyte ratio converged to 1 : 10. To know the regulation mechanism, the author investigated the ratio of basal melanocytes to suprabasal melanotytes. The ratios were nearly same by showing 0.142, 0.140, 0.118, 0.104 respectively. These results suggest that the ratio of melanocyte to keratinocyte in reconstructed stratified epidermis in vitro was not related with initial mixing ratio and was regulated by proliferation of melanocytes controled by corresponding keratinocytes.
Cell- and Tissue-Based Therapy ; Coculture Techniques* ; Epidermis* ; Follow-Up Studies ; Keratinocytes* ; MART-1 Antigen ; Melanocytes*

Objective: To investigate the ultrasonographic features and clinical pathological of liver metastasis in patients with melanoma. Methods: Thirteen patients with liver metastasis from melanoma treated in Tianjin Medical University Cancer Institute and Hospital from 2013 to 2019 were selected, and their ultrasonographic and clinicopathological characteristics were analyzed retrospectively. Results: Eleven of the 13 patients had multiple liver lesions. The maximum diameter of the lesions was (5.89±2.73) cm. Five cases of lesions were mixed echo (3 cases with high melanin content), 4 cases of lesions were hyperechoic (3 cases with low melanin content), 3 cases of lesions were hypoechoic (all with high melanin content), 1 case of lesions were equal echo (with high melanin content). The lesions in 11 patients had clear boundaries, while other 2 patients lacked the clear borders. Cystic areas were present in the lesions of 3 patients. Six cases had irregular lesions (lobulated), and 7 cases had regular lesions (round, oval). There were acoustic halos around the lesion in 9 cases and smooth and uneven acoustic halos in 5 cases. The results of immunohistochemistry showed that 11 cases were positive for S-100, HMB45 and Melan-A. One patient was not tested for HMB45, while S-100 and Melan-A were positive. One patient did not undergo Melan-A test, while S-100 and HMB45 were positive. Conclusion: Most of the liver metastases of melanoma are mixed echo or hyperechoic, most of them are nodular with clear boundaries combined with vocal halo, and a few of the lesions have cystic areas.
Humans ; Liver Neoplasms/secondary* ; MART-1 Antigen ; Melanins ; Melanoma/pathology* ; Retrospective Studies

Adrenohepatic fusion is the union of the liver and adrenal gland with close intermingling of their respective parenchymal cells. Adrenal cortical adenoma arising in adrenohepatic fusion tissue is extremely rare, although adrenohepatic fusion itself is relatively common. Here we report a case of a 59-year-old man with a mass in the right lobe of his liver. The mass showed slight hyperattenuation during arterial phase and hypoattenuation during portal phase on dynamic computed tomography with contrast enhancement. On pathology, the mass consisted of round to polygonal cells with clear microvesicular or eosinophilic cytoplasm, arranged in nests or in a trabecular pattern. The tumor cells were positive for inhibin and melan-A, but negative for Hep Par-1. In the periphery of the mass, adrenohepatic fusion was identified between the liver and adrenal gland, and was simultaneously resected with the mass. We report this rare case, and discuss its clinical implications, especially the differential diagnosis with hepatocellular carcinoma.
Adrenal Glands ; Adrenocortical Adenoma ; Carcinoma, Hepatocellular ; Cytoplasm ; Diagnosis, Differential ; Eosinophils ; Humans ; Inhibins ; Liver ; MART-1 Antigen ; Middle Aged

BACKGROUND: Bacteria associated with marine invertebrates are a rich source of bioactive metabolites. OBJECTIVE: The effects of marine bacteria extracts on pigmentation were investigated to find novel whitening agents. METHODS: The marine bacteria collected near Gangwha Island in Korea were isolated and extracted using organic solvent. The organic extracts were screened and selected using the cell free tyrosinase activity. The whitening effects of the selected extract were further investigated using cultured melanocytes, cultured skin and in vivo zebrafish. The whitening mechanism of the marine extract was also investigated. RESULTS: The marine bacterial methylene chloride extract reduced the pigmentation of Melan-a cells, human melanocytes, cultured skin and in vivo zebrafish. The decrease in pigmentation was due to the inhibition of tyrosinase activity and the expression of tyrosinase and microphthalmia-associated transcription factor protein. These bacteria were identified as a novel Pseudomonas species. CONCLUSION: The methylene chloride extract of marine pseudomonas species possesses a whitening effect. Further chemical isolation and characterization of the active compounds from this marine bacterial extract are needed.
Bacteria ; Humans ; Invertebrates ; Korea ; MART-1 Antigen ; Melanocytes ; Methylene Chloride ; Microphthalmia-Associated Transcription Factor ; Monophenol Monooxygenase ; Pigmentation ; Pseudomonas ; Skin ; Zebrafish

Spindle cell squamous cell carcinoma (SCSCC) is relatively uncommon, but may be encountered. It poses a challenge in the differential diagnosis in that it includes other spindle cell neoplasms. An 81-year-old female with a raised and exophytic plaque with central ulceration surrounding erythematous patches of the left lower extremities, which was gradually and very slowly increasing in size was admitted to our hospital. After resection, conventional histopathological investigation showed spindle-shaped cells showing hyperchromatic nuclei and mitosis, infiltrating the dermis in a storiform pattern. Immunohistochemical analysis revealed that SCSCC was positive for cytokeratins (AE1/AE3, CAM 5.2, 34betaE12) and mesenchymal markers (vimentin, SMA), but was negative for p63, CD34, CD68, melan A and S-100.
Carcinoma, Squamous Cell ; Dermis ; Diagnosis, Differential ; Female ; Humans ; Keratins ; Leg ; Lower Extremity ; MART-1 Antigen ; Mitosis ; Ulcer

Epithelioid angiomyolipoma (EAML) of liver is a rare neoplasm. Hepatic EAML is often misdiagnosed as other neoplasms such as hepatocellular carcinoma due to non-specific clinical and radiologic features. The morphologic features under microscope and immunohistochemistry staining profile are important in the diagnosis EAML. Here, we report a case of 52-year-old man who found 1.2 cm mass in liver by routine checkup. On the impression of hepatocellular carcinoma, lateral sectionectomy of the liver was done. Microscopically, the tumor is composed of predominant epithelioid cells with vascular component and foamy cells. These cells were positive for HMB45, MelanA, and smooth muscle actin and negative for epithelial membrane antigen. The final diagnosis was hepatic EAML.
Actins ; Angiomyolipoma* ; Carcinoma, Hepatocellular ; Diagnosis ; Epithelioid Cells ; Humans ; Immunohistochemistry ; Liver* ; MART-1 Antigen ; Middle Aged ; Mucin-1 ; Muscle, Smooth ; Perivascular Epithelioid Cell Neoplasms