[Histological spectrum of malignant melanoma]

Extensive Scalp Melanoma in an Elderly Female: A Case Report and Literature Review

Scalp melanoma is a rare and aggressive form of skin cancer. Its occurrence in the elderly population poses unique challenges due to factors such as delayed diagnosis and comorbidities. We present a case of extensive scalp melanoma in an elderly female to highlight the clinical presentation, diagnostic process, treatment modalities, and outcomes. Biopsy and histopathological analysis showed the presence of dysplastic nevi arising in pigmented melanocytic nevi, with uncertain pagetoid spread of atypical melanocytes. The management involved complete excision with safety margins and immunotherapy based on melanoma guidelines. This case underscores the importance of early detection and tailored treatment strategies in managing melanoma in elderly patients.

Actualities in the Morphology and Immunohistochemistry of Cutaneous and Ocular Melanoma: What Lies Ahead? A Single-Centre Study

Melanoma is the most aggressive melanocytic tumor whose incidence is continuously increasing worldwide.

METHODS

We highlight the morphological, immunohistochemistry, and particularities of various melanoma types based on the cases diagnosed in our department from 2017 to 2021.

RESULTS

We present 100 melanoma cases and one capsular nevus case. The most common type was nodular melanoma. The immunohistochemistry markers used were SRY-box transcription factor 10 (SOX10), S100 protein, human melanoma black 45 (HMB45), and melanoma antigen recognized by T cells 1 (Melan-A). Uveal melanoma and conjunctival melanoma represent particular tumors with independent prognostic factors. Uveal melanoma requires assessment of macrophages, microvascularisation, and mitoses. Sentinel lymph node metastases are essential targets that provide staging tools. Conjunctival melanoma and capsular nevi are diagnostic pitfalls.

CONCLUSION

Melanoma can appear in various forms, and sometimes the diagnosis might be unclear. Today, immunohistochemistry remains the most important tool in confirming the diagnosis and prognosis for this type of neoplasia.

Nodular malignant melanoma in vulvar skin without pigmentation: a case report

Background

Polypoid nodule growing without apparent pigmentation on the vulvar skin usually reminds us of the diagnostic pitfall, which is commonly and mistakenly diagnosed as other types of tumors. Although there are several manifestations of amelanotic melanoma are known, these malignancies are usually pigmented because they are derived from melanocytes containing melanin. However, amelanotic melanomas are easily misdiagnosed or their diagnoses were commonly delayed due to lack of pigmentation. Therefore, a solitary polypoid nodule is worth noting and further reporting. Particularly, the clinical characteristics and outcomes of the solitary polypoid nodule are rare in Asian patients.

Case presentation

We presented an interesting case of a 33-year-old female with a solitary polypoid nodule without apparent pigmentation on her vulvar skin. Her medical history was unclear, no ulcer was seen in the lesion area, and dermatoscopy was indicated a possible tumorous change, which has caught the attention of clinicians, and then further examined by the pathologist. The final diagnosis was nodular malignant melanoma (NM) (Breslow thickness 9.5mm, Clark level 4).

Conclusions

Hence, though reviewing this case record, the relevant literature and NM-related materials, we suggest that the combination of skin imaging technology and histopathological examination could provide us a better understanding and reduce the possibility of misdiagnosis in clinic practice.

Expression of HMB45, MelanA and SOX10 is rare in non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) and melanoma are frequent entities in routine diagnostics. Whereas the differential diagnosis is usually straight forward based on histomorphology, it can be challenging in poorly differentiated tumors as melanoma may mimic various histological patterns. Distinction of the two entities is of outmost importance as both are treated differently. HMB45 and MelanA are recommended immunohistological markers for melanoma in this scenario. SOX10 has been described as an additional marker for melanoma. However, comprehensive large-scale data about the expression of melanoma markers in NSCLC tumor tissue specimen are lacking so far.

METHODS

Therefore, we analyzed the expression of these markers in 1085 NSCLC tumor tissue samples. Tissue microarrays of NSCLC cases were immunohistochemically stained for HMB45, MelanA, and SOX10. Positivity of a marker was defined as ≥1% positive tumor cells.

RESULTS

In 1027 NSCLC tumor tissue samples all melanoma as well as conventional immunohistochemical markers for NSCLC could be evaluated. HMB45, MelanA, and SOX10 were positive in 1 (< 1%), 0 (0%) and 5 (< 1%) cases. The HMB45 positive case showed co-expression of SOX10 and was classified as large cell carcinoma. Three out of five SOX10 positive cases were SqCC and one case was an adenosquamous carcinoma.

CONCLUSIONS

Expression of HMB45, MelanA and SOX10 is evident but exceedingly rare in NSCLC cases. Together with conventional immunomarkers a respective marker panel allows a clear-cut differential diagnosis even in poorly differentiated tumors.

[Diagnostics of malignant melanoma of the skin : Recommendations of the current S3 guidelines on histology and molecular pathology]

The updated S3 guidelines on malignant melanoma were established in August 2016. The principles of diagnostics and classification are based on the histopathological results from the primary tumor and if necessary the sentinel lymph nodes. The most important factor for prognosis is the tumor thickness according to Breslow and the detection of sentinel node micrometastases. The surgical safety margin after excision is dependent on the tumor thickness. Furthermore, ulceration of the primary tumor and presence of mitosis in melanomas less than 1 mm in thickness are also considered in the T‑classification. The sentinel lymph nodes should be prepared according to established procedures using HE staining and immunohistochemical methods. The largest tumor diameter of a micrometastasis should be measured in tenths of a millimeter (Rotterdam classification). Molecular pathology testing for mutations in the BRAF and NRAS oncogenes should be carried out in patients with metastatic disease or surgically non-resectable tumors. In addition c-KIT mutations should be tested in acral lentiginous and mucosal melanomas. Treatment with signal transduction inhibitors is possible when mutations have been detected.

Dermatopathology 101. Part 2 - Skin tumors

The present CME article highlights fundamental aspects with respect to the histopathology of the most common skin tumors (epidermal, adnexal, melanocytic, and mesenchymal), their laboratory workup, as well as the importance of supplementary immunohistochemical and molecular studies. The information provided is meant to assist experienced clinicians in choosing the correct biopsy technique and in interpreting dermatopathology reports, and to provide dermatology residents with a better understanding of dermatopathology. Similar to inflammatory dermatoses, the diagnosis of skin tumors, too, requires the close cooperation between clinicians and dermatopathologists. The diagnostic quality and the resultant therapeutic approach can be significantly improved if this collaboration is based on the same dermatological understanding.