Advances in Merkel cell carcinoma from a pathologist's perspective.

Merkel cell carcinoma (MCC) is a rarely made but potentially devastating diagnosis. While local disease might be cured by surgery and radiotherapy, advanced disease is usually rapidly progressive and fatal. Until very recently, the only approach to metastatic MCC was cytotoxic chemotherapy with results so disappointing that current treatment guidelines discourage its use and recommend clinical trial as a more viable treatment option. Fortunately, recent advances in the understanding of the molecular pathogenesis of this tumour have produced a wide variety of experimental treatments for MCC, some of which are quite promising. The most current information regarding the diagnosis, staging, management of this tumour is briefly presented as well as new insights into the molecular basis of MCC and therapeutic approaches to MCC.

Unstable solar lentigo: A defined separate entity.

An unstable solar lentigo is a solar lentigo with areas of melanocytic hyperplasia not extending past the margin of the lesion. They are discrete, macular, pigmented lesions arising on sun-damaged skin and a subset of typical solar lentigos. Clinically they differ from usual solar lentigines in often being solitary or larger and darker than adjacent solar lentigines. These lesions are of clinical importance as they can arise in close proximity to lentigo maligna and in a single lesion there can be demonstrated changes of solar lentigo, unstable solar lentigo and lentigo maligna. These observations led us to conjecture that unstable solar lentigos could be a precursor lesion to lentigo maligna. In this article we examine the possibility that lentigo maligna can arise within a solar lentigo through an intermediate lesion, the unstable solar lentigo. We propose that the histopathological recognition of this entity will allow for future research into its behaviour and thus management. We review difficulties in the diagnosis of single cell predominant melanocytic proliferations and the concept of unstable lentigo in view of the literature and clinical experience supporting the proposal of its recognition as a separate entity.

Nodular melanoma: five consecutive cases in a general practice with polarized and non-polarized dermatoscopy and dermatopathology.

BACKGROUND: The incidence of nodular melanoma (NM) has been consistently described as at least 10-15% of total melanomas for over 15 years despite advances in diagnostic algorithms and medical technology. NMs are strongly correlated with faster rates of growth and poorer prognosis and thus provide clinicians with a challenge for early recognition. OBJECTIVE: To evaluate diagnostic clues of consecutive histopathologically proven NMs in one general practice with particular emphasis on dermatoscopic characteristics and compare this to the published literature. METHOD: A retrospective observational study was performed of five consecutive histologically proven NM, from a total of 212 consecutive melanomas from a general practice in Brisbane, Queensland, Australia. Dermatoscopic images, both polarized and non-polarized, which appears to be a unique resource, and dermatopathologic slides were available for all lesions. RESULTS: All of the NMs in this series were pigmented although one was hypomelanotic. Two of them were symmetrical. The most highly sensitive clues to NM were gray or blue structures and polarizing-specific white lines. LIMITATIONS: Due to the small number of NMs in this report no statistical significance can be attributed to the observational findings. CONCLUSION: THIS SMALL SERIES SUPPORTS WHAT IS ALREADY KNOWN: that a significant proportion of NMs may be dermatoscopically symmetrical but that known clues to melanoma are frequently present. Nodular lesions, pigmented or non-pigmented, should be excised to exclude NM if there is any clue to malignancy, regardless of symmetry, unless a confident specific benign diagnosis can be made.

Balloon cell melanoma in primary care practice: a case report.

A case of balloon cell melanoma encountered in a primary care skin cancer practice in Melbourne, Australia is presented. The presenting lesion was 6 mm in diameter, ulcerated, non-pigmented and without any algorithmic clues to melanoma. However the presence of terminal hairs caused the clinician to suspect that it was melanocytic. The lesion was reported as a balloon cell melanoma, Clark level 4, Breslow thickness 2 mm with a mitotic index of 4 per square mm. This is an extremely rare melanoma subtype. Author DW has encountered only two cases in a career involving in excess of one million signed out dermatopathology reports. A search of the literature has not discovered any previously published dermatoscopy images of a balloon cell melanoma.

Metastatic hepatocellular carcinoma to the skin staining positive with HMB-45.

Hepatocellular carcinoma (HCC) is uncommonly observed as a cutaneous metastasis. We report a 76-year-old man with metastatic HCC to the skin of the nasal ala, diagnosed antecedent to the primary tumor. HCC was confirmed by positive immunostaining with Hep Par 1 in tissue from the metastasis and from a needle biopsy of the primary lesion. In addition, tumor cells from both the metastasis and liver stained positive with HMB-45. To our knowledge, HMB-45 positive staining has not been reported in either primary or metastatic HCC.