Sry-related HMg-Box gene 10 (SOX10) is a nuclear transcription factor that plays an important role in melanocytic cell differentiation. It has been shown to be a sensitive marker of melanoma including spindle and desmoplastic subtypes. We assessed its frequency of expression in melanoma, carcinoma, benign nevi, and non-neoplastic tissues with routine immunohistochemistry for SOX10. The 109 primary melanoma included 49 epithelioid, 19 spindle cell, 22 desmoplastic, and 19 mixed spindle cell/desmoplastic melanoma. All primary, except 8 desmoplastic melanoma, and 11 metastatic melanoma were strongly and diffusely nuclear SOX10-positive. Six desmoplastic melanoma had ≤10% cells positive, and 2 were <50% positive, all of 3+ intensity. Eighteen of 149 (12%) breast carcinoma were SOX10-positive. All 24 ovarian, 23 endometrial, 26 lung, and 25 colon carcinoma were SOX10-negative. All 43 benign nevi, 18 dysplastic nevi, 68 non-neoplastic and benign skins, and all 56 non-neoplastic breast tissue were SOX10-positive. The sensitivity and specificity for SOX10 in the diagnosis of melanoma are 1.0 and 0.93, respectively; the positive and negative predictive values are 0.87 and 1.0, respectively. SOX10 is a sensitive, specific marker for melanoma. As benign nevi also express SOX10, it cannot be used to differentiate between benign and malignant pigmented skin lesions. Only a small number of breast carcinoma (12%), and breast lobules, express SOX10; no carcinoma of the ovary, endometrium, lung, or colon expressed SOX10.

SOX10 expression in malignant melanoma, carcinoma,and normal tissues

Nevus depigmentosus is a congenital disorder characterized by a nonprogressive hypopigmented lesion, which may not be apparent at birth. Thus, it is sometimes difficult to differentiate vitiligo from nevus depigmentosus only by clinical features. We postulated that the histologic changes in lesional and perilesional skin might be different in the 2 conditions. We took biopsies from both lesional and perilesional skin of 100 cases of vitiligo to assess the number of melanocytes, the amount of melanin, dermal inflammatory infiltrate, and other changes. We compared them with 30 cases of nevus depigmentosus. Histologically, lesions of vitiligo showed more basal hypopigmentation and dermal inflammation than perilesional normal skin. With Fontana-Masson staining, 16% of cases of vitiligo showed the presence of melanin. The ratio of pigmented area to epidermal area was 0.06% in vitiligo, whereas 17% in perilesional normal skin and 8.9% in nevus depigmentosus. In NKI/beteb staining, 12% of vitiligo showed the presence of melanocytes, and their average number was 7.68 per square millimeter. The number of melanocytes was also decreased in nevus depigmentosus but not as much as in vitiligo. We also confirmed the presence of melanocytes in 1 of 3 cases of vitiligo by electron microscopy. In conclusion, there are a few melanocytes and melanin in some cases of vitiligo. Therefore, the diagnosis of vitiligo should be made considering these points.

Histopathologic features in vitiligo.

Loss of S100 antigenicity in metastatic melanoma

KBA.62: a useful marker for primary and metastatic melanomas.

Actinomycosis is a chronic suppurative infection of the cervicofacial region caused by Actinomyces species, which are anaerobic, gram-positive filamentous bacteria. Although actinomycosis has a propensity for involving the oral cavity, rare cases of actinomycosis involving the temporal bone have been published. We report the case of a 14-year-old girl who presented with clinical, audiometric, and radiologic findings consistent with right chronic suppurative otitis media that persisted despite tympanomastoidectomy. Findings on histologic evaluation of a specimen obtained during revision surgery were consistent with a diagnosis of actinomycosis. Although actinomycosis of the temporal bone is rare, it should be considered in the differential diagnosis of chronic suppurative temporal bone infections that are resistant to standard therapy.

https://journals.sagepub.com/doi/pdf/10.1177/014556130408300512

Actinomycosis of the temporal bone: a report of a case.

Another case of actinomycosis of the ear is described in a nine-year-old boy, drawing attention to the increasing incidence of diseases of the ear considered to be rare. The patient presented with the clinical signs of chronic purulent otitis media, not responding to conservative treatment. After the diagnosis of actinomycosis was established the patient was treated by surgery and long-term antibiotic medication, responding favourably.

Actinomycosis of the middle ear.

In certain primary and metastatic malignant melanomas diagnostic problems may arise due to their cytologic features and/or absence of synthesis of melanin. As the "classic" combination of S-100 protein and HMB-45 may occasionally fail to stain cells of malignant melanoma, we have tested a series of commercially accessible antibodies which were so far not compared by other authors in the three most frequent subtypes of this tumor. In surgical specimens from 104 cutaneous malignant melanomas (40 nodular melanomas, 46 superficially spreading malignant melanomas and 18 lentigo maligna melanomas) the staining intensity and the proportion of neoplastic cells stained with antibodies to S-100 protein, HMB-45, NKI/C3, NKI/beteb, MART 1 (Melan A), KBA 62 and Mitf was semiquantitatively analysed. The use of this group of antibodies against melanoma-associated antigens revealed it to be a favourable supplement for the bioptical or cytological diagnosis of malignant melanoma in case the traditional/conventional combination of S-100 protein and HMB-45 antibody fails. According to the authors' experience the antibody against KBA 62 has shown to be the most effective antibody followed by the antibodies against MART-1 (Melan A) and NKI/C3.

Immunohistochemical study of melanocytic differentiation antigens in cutaneous malignant melanoma. A comparison of six commercial antibodies and one non-commercial antibody in nodular melanoma, superficially spreading melanoma and lentigo maligna melanoma.

Benický M

Papers

Actinomycosis of the middle ear.

Immunohistochemical study of melanocytic differentiation antigens in cutaneous malignant melanoma. A comparison of six commercial antibodies and one non-commercial antibody in nodular melanoma, superficially spreading melanoma and lentigo maligna melanoma.