Cytologic diagnosis of metastatic melanoma by FNA: A practical review

Abstract

Malignant melanoma (MM) is a highly aggressive neoplasm with a growing worldwide incidence. It is not uncommon that the disease is already metastatic at the time of the first diagnosis. Regional lymph nodes and skin are the first and most common metastatic sites, followed by distant visceral sites (lungs, liver, and central nervous system) and bone. In this clinical setting, fine-needle aspiration (FNA) often represents the first diagnostic approach. FNA is a useful tool to obtain a rapid and accurate diagnosis, in conjunction with ancillary techniques and molecular analysis, as recommended by recent guidelines.The aim of this review was to describe the cytomorphology, immunocytochemical tools, and molecular tools used for the diagnosis of MM metastases on FNA. Cancer Cytopathol 2021;0:1-12.

PRAME Immunocytochemistry for the Diagnosis of Melanoma Metastases in Cytological Samples

“…Fine-needle aspiration cytology is widely applied for the diagnosis of CM metastases, mainly in patients with a known history of CM. However, the diagnosis of CM from cytological samples may be challenging, as CM may present heterogeneous morphological findings [4]. Moreover, pigmented histiocytes may be present in the sample, and may be confused with neoplastic cells [4].…”

“…However, the diagnosis of CM from cytological samples may be challenging, as CM may present heterogeneous morphological findings [4]. Moreover, pigmented histiocytes may be present in the sample, and may be confused with neoplastic cells [4]. Nevertheless, a correct diagnosis of CM metastases is mandatory, because cytological samples may also be used for the predictive evaluation of the BRAF molecular status of the neoplasm, and because immunotherapy has recently been introduced for patients affected by metastatic CM [3].…”

“…Moreover, FNAC is a useful tool to obtain neoplastic cells to perform molecular evaluations, for a predictive purpose, on metastatic neoplasms [3]. The diagnosis of CM metastasis from a cytological sample may be challenging, as the morphology of the neoplastic cells is widely variable, including several types, such as epithelioid, plasmacytoid, spindle, small, rhabdoid, signet-ring, myxoid and balloon cells [4]. In this setting, immunocytochemistry (ICC) plays a crucial role in diagnosis, when morphology alone has insufficient diagnostic accuracy [5].…”

Comparative efficacy and safety of targeted therapies for BRAF-mutant unresectable or metastatic melanoma: Results from a systematic literature review and a network meta-analysis

“…A number of approved treatment options currently exist for BRAFmutant patients with unresectable or metastatic melanoma (MM), and effective diagnosis tools are available for assessing BRAF mutational status [1][2][3]. Clinician judgment drives individualized treatment decisions based on characteristics of the patient and of the disease [4].…”

Image‐based response assessment during immunotherapy in skin cancer

“…Hereby especially fine-needle aspiration (FNA) biopsy is often a reasonable approach. 5 Biopsies can give precise insights into the composition of the tumor with its stromal reaction, tumor microenvironment as well as a possible immune infiltrate. Furthermore, the tissue can be analyzed for genetic and epigenetic alterations which may have therapeutic implications or indicate therapy response.…”