Immunohistochemical characteristics of melanoma

Metastasis in the wild: investigating metastasis in non-laboratory animals

Humans are not the only species to spontaneously develop metastatic cancer as cases of metastasis have been reported in a wide range of animals, including dinosaurs. Mouse models have been an invaluable tool in experimental and clinical metastasis research, with the use of genetically-engineered mouse models that spontaneously develop metastasis or ectopic/orthotopic transplantation of tumour cells to wildtype or immunodeficient mice being responsible for many key advances in our understanding of metastasis. However, are there other species that can also be relevant models? Similarities to humans in terms of environmental exposures, life-span, genetics, histopathology and available therapeutics are all factors that can be considered when looking at species other than the laboratory mouse. This review will explore the occurrence of metastasis in multiple species from a variety of domestic, captive and free-living veterinary cases to assist in identifying potential alternative experimental and clinical research models relevant to humans.

Malignant Melanoma: Diagnostic and Management Update

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Summarize the changes to the American Joint Committee on Cancer Eighth Edition Melanoma Staging System. 2. List advances in genetic, molecular, and histopathologic melanoma diagnosis and prognostication. 3. Recommend sentinel lymph node biopsy and appropriate surgical margins based on individualized patient needs. 4. Recognize the currently available treatments for in-transit metastasis and advanced melanoma. 5. Describe current and future therapies for melanoma with distant visceral or brain metastases.

SUMMARY

Strides in melanoma surveillance, detection, and treatment continue to be made. The American Joint Committee on Cancer Eighth Edition Cancer Staging System has improved risk stratification of patients, introduced new staging categories, and resulted in stage migration of patients with improved outcomes. This review summarizes melanoma advances of the recent years with an emphasis on the surgical advances, including techniques and utility of sentinel node biopsy, controversies in melanoma margin selection, and the survival impact of time-to-treatment metrics. Once a disease manageable only with surgery, a therapeutic paradigm shift has given a more promising outlook to melanoma patients at any stage. Indeed, a myriad of novel, survival-improving immunotherapies have been introduced for metastatic melanoma and more recently in the high-risk adjuvant setting.

Morphologic and Immunohistochemical Characteristics of Anorectal Melanoma

Anorectal melanoma is a rare aggressive disease. Due to its rarity and considerable histologic and immunohistochemical variabilities, misdiagnosis as lymphoma, carcinoma, sarcoma, and/or gastrointestinal stromal tumor is not uncommon, particularly in amelanotic cases. We reviewed histologic features and immunohistochemical stains of 19 anorectal melanoma cases. Histopathologic features were evaluated including junctional activity, melanin pigment, and morphologic features. Immunohistochemical stains were performed using Sox10, S100 protein, HMB-45, melan-A, CD56, and cytokeratins. Epithelioid histopathologic morphology was observed in 63.2% of the cases followed by 47.4% of the cases with spindle-cell, 26.3% with lymphoma-like, and 26.3% with pleomorphic morphologies. Junctional melanocytic activity was seen in almost half of the cases. Melanin pigment was absent (amelanotic) in nearly 40% of the cases. Immunohistochemically, diffuse positive expression of Sox10, S100 protein, melan-A, and HMB-45 was seen in 100%, 40%, 53.3%, and 38.5% of the cases, respectively. Cytokeratins were negative and CD56 was positive in 2 cases. These findings indicate that anorectal melanomas often show one or combined histolopathologic features without presence of melanin pigment and absence of junctional melanocytic activity. Anorectal melanoma should be kept in mind in the differential diagnosis of malignant neoplasms of anorectal region with epithelioid, spindle-cell, lymphoma-like, and pleomorphic morphologies. Sox10 immunohistochemistry stain can be used as a first-line screening tool to avoid extensive or unnecessary workups and/or potential misdiagnosis.

Primary Malignant Melanoma of the Breast: A Report of Two Cases

Primary malignant melanoma of the breast (PMMB) is a rare tumor with only a few case reports available in the literature. We report two cases of PMMB, one derived from the breast parenchyma and the other from the breast skin. The first case consisted of atypical epithelioid cells without overt melanocytic differentiation like melanin pigments. The tumor cells showed diffuse positivity for S100 protein, tyrosinase, and BRAF V600E. However, the tumor cells were negative for cytokeratin, epithelial membrane antigen, and HMB-45. The second case showed atypical melanocytic proliferation with heavy melanin pigmentation. The tumor cells were positive for S100 protein, HMB-45, tyrosinase, and BRAF V600E. These two cases represent two distinct presentations of PMMB in terms of skin involvement, melanin pigmentation, and HMB-45 positivity. Although PMMB is very rare, the possibility of this entity should be considered in malignant epithelioid neoplasms in the breast parenchyma.

A novel report of a primary Merkel cell carcinoma lesion in the nasal vestibule

Merkel cell carcinoma (MCC) accounts for less than 1% of cutaneous malignancies. As the lesion may mimic benign entities, clinicians' differential should include rare entities to improve outcomes by early intervention. We present a case of primary MCC in the nasal vestibule requiring partial rhinectomy, suprahyoid lymphadenectomy, and radiation therapy.

Clinical features and prognosis of Asian patients with acral lentiginous melanoma who have nodal nevi in their sentinel lymph node biopsy specimen

BACKGROUND

Nodal melanocytic nevi (NNs) encountered during sentinel lymph node biopsy (SLB) for malignant melanoma are usually difficult to distinguish from metastatic melanoma. However, NNs have not been well studied in acral lentiginous melanoma (ALM) in Asian populations.

OBJECTIVE

To investigate the clinical characteristics and significance of NNs in SLB specimens from patients with ALM.

METHODS

We retrospectively analyzed 84 patients with ALM who underwent SLB between June 2010 and July 2017.

RESULTS

Of the 84 patients with ALM, 9 (10.7%) had NNs in their SLB specimens. NNs were significantly more common in SLB specimens than in specimens not obtained by SLB. The presence of pre-existing melanocytic lesions was found to be associated with NNs (P < .001). The 5-year overall survival was significantly higher in patients with ALM with NNs than in patients with a positive SLB result (P = .047). Distant recurrence in patients with ALM with NNs was significantly lower than in patients a positive SLB result (P = .03).

LIMITATIONS

The small sample size, single-center study design, and retrospective nature of the study were the limitations.

CONCLUSION

In Asian populations, the prevalence of NNs in ALM is similar to that reported in Europe and the United States. The rates of distant recurrence and overall survival in patients with ALM who have NNs are similar to those of patients who do not have metastatic melanoma.

Metastatic melanoma with balloon/histiocytoid cytomorphology after treatment with immunotherapy: A histologic mimic and diagnostic pitfall

Epithelioid cells with foamy cytoplasm (histiocytoid features) are typical histopathologic findings among benign and malignant histiocytic neoplasms such as xanthoma and atypical fibroxanthoma. However, these changes are unusual in melanoma, which is typically composed of nested and variably pigmented atypical epithelioid cells. Here, we report a patient with metastatic melanoma in lymph nodes presenting with prominent balloon cell/histiocytoid features expressing melanocytic markers, after treatment with nivolumab. This report suggests that the spectrum of neoplasms with histiocytoid features should be expanded to include melanoma, a pattern that, to the best of our knowledge, is uncommon, especially in the setting of post-neoadjuvant therapy.

Cofilin-1 levels and intracellular localization are associated with melanoma prognosis in a cohort of patients

Melanoma is an aggressive cancer with highly metastatic ability. We propose cofilin-1, a key protein in the regulation of actin dynamics and migration, as a prognostic marker. We determined cofilin-1 levels in a retrospective cohort of patients with melanomas and benign lesions of melanocytes (nevi) by immunohistochemistry. Higher cofilin-1 levels were found in malignant melanoma (MM) with Breslow Index (BI)>2 vs MM with BI<2, melanoma in situ (MIS) and nevi and also in MM with metastasis vs MM without detected metastasis. Kaplan-Meier survival curves were performed, clustering patients according to either the type of melanocytic lesions or cofilin-1 level. Survival curves demonstrated worse prognosis of patients with high vs low cofilin-1 levels. TCGA database analysis of melanoma also showed low survival in patients with upregulated cofilin-1 mRNA vs patients without alteration in CFL1 mRNA expression. As cofilin-1 has a dual function depending on its intracellular localization, we evaluated nuclear and cytoplasmic levels of cofilin-1 in melanoma and nevi samples by immunofluorescence. MM with high Breslow index and metastatic cells not only presented cytoplasmic cofilin-1, but also showed this protein at the nucleus. An increase in nuclear/cytoplasmic cofilin-1 mean fluorescence ratio was observed in MM with BI>2 vs MM with BI<2, MIS and nevi. In conclusion, an association of cofilin-1 levels with malignant features and an inverse correlation with survival were demonstrated. Moreover, this study suggests that not only the higher levels of cofilin-1, but also its nuclear localization can be proposed as marker of worse outcome of patients with melanoma.

The relationship between mitotic rate and depth of invasion in biopsies of malignant melanoma

Background

Malignant melanoma of the skin is a potentially lethal neoplasm that generally originates from atypical melanocytes in the dermal-epidermal junction. When the neoplasm penetrates into the dermis, several variables can affect the extent of its spread, among which depth of invasion has the most important prognostic value. Mitotic rate is another prognostic factor that reflects the biological behavior of the neoplasm.

Objective

This study was designed to evaluate the probable relationship between the depth of invasion of malignant melanoma and its mitotic rate.

Materials and methods

This study was performed on 50 excisional biopsy specimens that had received the diagnosis of malignant melanoma histopathologically. Tumor characteristics including Breslow thickness, Clark level, T-stage, and tumor mitotic rate were recorded.

Results

We observed that at higher Clark levels and higher T-stages, and the mean mitotic rate was significantly increased. Moreover, there was a positive and significant correlation between Breslow thickness and mitotic rate. We demonstrated that one unit increase in mitotic rate was correlated with 0.8 mm increase in Breslow thickness of the tumor.

Conclusion

In malignant melanoma, mitotic activity may probably indicate the depth of tumor invasion. Therefore, in incisional biopsies where depth of invasion cannot be accurately determined, the mitotic activity may be used to estimate Breslow thickness, which is necessary for planning surgical management.

MELANOMA IN GOLDEN AND KING WILDEBEESTS ( CONNOCHAETES TAURINUS)

Pigmentation of the skin is a crucial component in the pathogenesis of melanocytic neoplasms and other skin-related tumors, as melanin is known to function in both the absorbance of ultraviolet radiation and as an antioxidant. Very limited information exists regarding the incidence and metastatic potential of neoplastic conditions of the skin in game animals, especially wildebeests, relative to domestic animals. Four cases of cutaneous melanoma in color-variant golden and king wildebeests ( Connochaetes taurinus) (from 2014 to 2015) in South Africa were investigated. Melanoma in these captive animals was characterized using histopathology, transmission electron microscopy, and an immunohistochemistry panel, which consisted of monoclonal antibodies against three melanocytic markers: Melan A, PNL2, and S100. Overall, 2/4 cases (50%) of the melanocytic neoplasms stained strongly positive for all the melanocytic markers, while 4/4 cases (100%) stained positively for at least one of the markers. Cutaneous melanocytic neoplasia has not been reported in wildebeests; the current study suggests that selection of wildebeests for coat color potentially predisposes to this condition.

Acral melanoma foot lesions. Part 2: clinical presentation, diagnosis, and management

Acral melanoma (AM) is a rare subtype of cutaneous malignant melanoma found on acral skin, primarily on the soles of the feet. Although rare, it is the most common subtype of melanoma found in patients of African or Asian ethnicity and has a poor prognosis, often because of the more advanced stage of presentation at diagnosis. In the second of this two-part series, we review the clinical presentation, histopathology, diagnosis and management of AM. Clinically, AM presents as a variegated lesion with blue-black pigment and irregular borders on acral skin. A parallel-ridge pattern is a very specific dermoscopic finding for AM. The differential diagnoses of AM include acral naevus, pyoderma gangrenosum, pyogenic granuloma, verrucous carcinoma and peripheral neuropathy-induced foot ulcers. If there is a clinical suspicion of AM, an excisional biopsy should be taken. Once diagnosis is confirmed by histology, surgical excision is the standard treatment. Overall, dermoscopy and histopathology are key tools in the diagnosis of AM. A greater emphasis on melanoma screening and awareness is essential in minority populations to improve survival outcomes in AM.

Adrenal mass of unusual etiology: Ewing sarcoma in a young man

Ewing sarcoma and peripheral primitive neuroectodermal tumor belong to the Ewing sarcoma (ES) family of tumors originating from a primitive neural tube. We report a 31-year-old man who was admitted to the urology clinic with complaints of fever, nausea, and dysuria. A right-sided adrenal mass was detected during ultrasonography. The lesion was then evaluated with magnetic resonance imaging, which showed areas of necrosis amid heterogeneous solid areas. Whole body scan with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography and bone scan studies showed pulmonary and osseous metastatic foci. The mass and right kidney were removed by an open approach. An immunohistochemical and molecular workup enabled the diagnosis of ES. The patient also underwent radiotherapy and chemotherapy. The patient remained in fairly good health during the 18-month follow-up period, but showed progression of all metastatic foci and died 26 months after treatment. In conclusion, adrenal ES should be included in the differential diagnosis of nonfunctional adrenal lesions despite its rare occurrence.

Glucose metabolism and NRF2 coordinate the antioxidant response in melanoma resistant to MAPK inhibitors

Targeted therapies as BRAF and MEK inhibitor combination have been approved as first-line treatment for BRAF-mutant melanoma. However, disease progression occurs in most of the patients within few months of therapy. Metabolic adaptations have been described in the context of acquired resistance to BRAF inhibitors (BRAFi). BRAFi-resistant melanomas are characterized by an increase of mitochondrial oxidative phosphorylation and are more prone to cell death induced by mitochondrial-targeting drugs. BRAFi-resistant melanomas also exhibit an enhancement of oxidative stress due to mitochondrial oxygen consumption increase. To understand the mechanisms responsible for survival of BRAFi-resistant melanoma cells in the context of oxidative stress, we have established a preclinical murine model that accurately recapitulates in vivo the acquisition of resistance to MAPK inhibitors including several BRAF or MEK inhibitors alone and in combination. Using mice model and melanoma cell lines generated from mice tumors, we have confirmed that the acquisition of resistance is associated with an increase in mitochondrial oxidative phosphorylation as well as the importance of glutamine metabolism. Moreover, we have demonstrated that BRAFi-resistant melanoma can adapt mitochondrial metabolism to support glucose-derived glutamate synthesis leading to increase in glutathione content. Besides, BRAFi-resistant melanoma exhibits a strong activation of NRF-2 pathway leading to increase in the pentose phosphate pathway, which is involved in the regeneration of reduced glutathione, and to increase in xCT expression, a component of the xc—amino acid transporter essential for the uptake of cystine required for intracellular glutathione synthesis. All these metabolic modifications sustain glutathione level and contribute to the intracellular redox balance to allow survival of BRAFi-resistant melanoma cells.

A quantitative comparison between SOX10 and MART-1 immunostaining to detect melanocytic hyperplasia in chronically sun-damaged skin

Histologic differentiation of melanoma in situ (MIS) from solar keratosis on chronically sun-damaged skin is challenging. The first-line immunostain is usually MART-1/Melan-A, which can exaggerate the epidermal melanocytes, causing a diagnostic pitfall for MIS. By comparing MART-1 and SOX10 immunostaining, we scored the percentage of epidermal melanocytes per 2-mm diameter fields in pigmented actinic keratosis (n = 16), lichenoid keratosis (n = 7), junctional melanocytic nevus (n = 6), keratosis with atypical melanocytic proliferation (n = 17) and MIS (n = 10). These cases represented an older population (68 years median age) and the head and neck (50%) was the most common anatomic site. MART-1 score was significantly higher than SOX10 (P value <.05) in solar keratoses, but showed no difference in detecting melanocytic proliferations, demonstrating their equal detection rate of melanocytes. The sensitivity of both MART-1 and SOX10 was 100%, while their specificities were 17% and 96%, respectively. These results show that SOX10 is more specific than MART-1 in distinguishing epidermal melanocytes on sun-damaged skin by avoiding overdiagnosis of melanoma.

Pathology of Melanotic Schwannoma

CONTEXT.—

Melanotic schwannoma (MS) is a nerve sheath tumor with a uniform composition of variably melanin-producing Schwann cells and metastatic potential. The MS is an uncommon neoplasm, accounting for less than 1% of all nerve sheath tumors, with a predilection for spinal nerve involvement. Microscopically, the tumors are characterized by spindle and epithelioid cells arranged in interlacing fascicles, with marked accumulation of melanin in neoplastic cells and associated melanophages. The MSs are frequently associated with Carney complex, showing features of psammoma bodies and adipose-like cells. Strict criteria of malignancy in MS are not well developed, although a combination of worrisome histologic features (large, vesicular nuclei, with macronucleoli, brisk mitotic activity, and necrosis) raises concern for aggressive behavior.

OBJECTIVE.—

To review the current status of the MS literature, discussing putative etiology, histopathology, current genetics, and differential diagnoses, including overlap with other pigmented tumors.

DATA SOURCES.—

Search of PubMed (National Center for Biotechnology Information, Bethesda, Maryland) and the authors' own experiences.

CONCLUSIONS.—

The occurrence of MS at several unusual anatomic sites and its spectrum of morphologic patterns can result in significant diagnostic difficulty, and correct diagnosis is particularly important because of its high tendency to recur locally and to metastasize, which highlights the importance of diagnostic recognition, ancillary molecular genetic testing, and close clinical follow-up of patients with MS.

Loss of Conventional Melanocytic Markers in Malignant Melanoma and Lymph Node Metastasis; an Uncommon but Dangerous Pitfall

Although malignant melanomas exhibit a wide range of immunophenotypes, concurrent loss of all 3 conventional melanocytic markers (S-100, Melan-A, and HMB-45) is relatively rare. We report a case of primary malignant melanoma with lymph node metastasis, both exhibiting loss of immunoreactivity for conventional melanocytic markers, while aberrantly expressing epithelial antigenicity (pancytokeratin, CAM 5.2).

Assessing Genetic Expression Profiles in Melanoma Diagnosis

Most melanocytic tumors can be characterized as a benign nevus or a melanoma by a trained pathologist using traditional histopathological methods. However, a minority demonstrates ambiguous features and continues to be a diagnostic challenge. Genetic expression profiling (GEP) assays have been developed in an effort to resolve this dilemma. These assays measure mRNA levels of specified genes using reverse transcription quantitative polymerase chain reaction technology. The development of GEP assays, methodology, challenges associated with GEP validation and testing, and the suitability of a currently available GEP test for clinical use are reviewed.

Application of Immunohistochemistry in Undifferentiated Neoplasms: A Practical Approach

Context.—

Advances in interventional technology have enhanced the ability to safely sample deep-seated suspicious lesions by fine-needle aspiration procedures. These procedures often yield scant amounts of diagnostic material, yet there is an increasing demand for the performance of more ancillary tests, especially immunohistochemistry and, not infrequently, molecular assays, to increase diagnostic sensitivity and specificity. A systematic approach to conserving diagnostic material is the key, and our previously proposed algorithm can be applied aptly in this context.

Objective.—

To elaborate a simple stepwise approach to the evaluation of cytology fine-needle aspiration specimens and small biopsy tissue specimens, illustrating the algorithmic application of small panels of immunohistochemical stains in providing an accurate diagnosis with scant amounts of tissue, including the potential pitfalls that may arise while using immunohistochemical staining on small quantities of tissue.

Data Sources.—

The sources include literature (PubMed), the first Chinese American Pathologists Association Diagnostic Pathology Course material, and the review authors' research data as well as practice experience. Seven examples selected from the CoPath database at Geisinger Medical Center (Danville, Pennsylvania) are illustrated.

Conclusions.—

A stepwise approach to the evaluation of fine-needle aspiration and small biopsy tissue specimens in conjunction with a small panel of select immunohistochemical stains has been successful in accurately assessing the lineage/origin of the metastatic tumors of unknown primaries. The awareness of the common pitfalls of these biomarkers is essential in many instances.

Congenital and infantile malignant melanoma of the scalp: A systematic review

Congenital and infantile malignant melanomas are rare and typically carry poor prognosis. The purpose of this article was to review the data on congenital and infantile malignant melanomas of the scalp in order to understand its presentation, diagnosis, management, and outcomes of congenital melanoma of scalp. We searched PubMed, CINAHL and Cochrane databases. Ten cases of congenital and 3 cases of infantile malignant melanoma of scalp were identified. The diagnosis was confirmed by biopsy and histological analysis for confirmation. The prognosis depends on the origin of disease (congenital melanocytic nevus, transplacental metastasis, or de-novo), tumor thickness, the presence of ulceration and/or necrosis, and anatomic site (scalp lesions having poor prognosis). The most commonly used treatment of the reported cases of congenital and infantile melanoma was surgical excision of the primary lesion. Further modes of treatment may be extrapolated from the treatment of childhood and adult melanomas.

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Congenital and infantile malignant melanomas are rare.

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Surgery is the mainstay of treatment.

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Prognosis of the condition remains poor.

Spindle Cell Melanoma and Interdigitating Dendritic Cell Sarcoma: Do They Represent the Same Process?

Intranodal spindle cell lesions on biopsy are problematic for a surgical pathologist, often requiring an extensive immunohistochemical evaluation with variable and frequently unsatisfactory results. In the absence of a history of malignancy, the differential diagnosis of a spindle cell tumor must include both a primary nodal proliferation and a metastatic process. Particularly challenging are those lesions that share morphologic and immunohistochemical features; spindle cell melanomas (SCM) and interdigitating dendritic cell sarcomas (IDCS) belong to this category. At present, electron microscopy is the only method proposed to distinguish between the 2 entities; however, this method is often unavailable and impractical. In this study, we assessed the comparative immunophenotypes of 18 cases of SCM and 8 cases of IDCS, with particular emphasis on the expression of MUM-1, β-catenin, SOX-10, MiTF, and p75. Our results showed nearly equivalent staining patterns and profiles; 12% and 17% of IDCS and SCM were labeled for MUM-1, 75% and 83% stained for β-catenin, 0% and 24% expressed MiTF, and 100% and 94% labeled for p75, respectively. All cases of IDCS and SCM displayed strong nuclear reactivity for SOX-10. On the basis of our study and pertinent literature, the morphologic and immmunophenotypic features of SCM and IDCS appear to be virtually indistinguishable from one another, raising the question as to whether these 2 entities represent a pathobiologically similar or even identical process.

Epithelioid hemangioendothelioma of the spine: case report and review of the literature

Epithelioid hemangioendothelioma (EHE) has been described as a rare vascular bone lesion with histological features between hemangioma and high-grade angiosarcoma. Spinal EHE is a quite rare disease with few case reports and series reported in the literature. The tumor cells are positive for vimentin, CD31and CD34, factor VIII related antigen, ERG, and FLI1. Radiological features are not specific; it may appear as an osteolytic lesion. It can present as a multifocal disease in 40% of cases. No clear correlation with age and sex; however, it is slightly more common in males. Focal neck or back pain is the most common presenting symptom. The natural history of spinal EHE is unpredictable, and currently, there is no standard of care for treatment. Treatment options include preoperative embolization, and surgical resection followed by radiotherapy and/or chemotherapy. A 34-year-old previously healthy male presented with mid-thoracic back pain. Magnetic resonance imaging (MRI) of the spine revealed a decrease in vertebral body height at T5 with an enhancing mass. He underwent T5 balloon kyphoplasty and needle vertebral body biopsy. Results of the biopsy samples were non-diagnostic. Approximately 3 months after surgery, the patient presented with unsteady gait. A subsequent MRI revealed progression of the T5 compression fracture with cord compression. The patient subsequently underwent T4-T6 bilateral posterior decompression for epidural tumor and T3-T7 posterior instrumentation with pedicle screws. Pathology of the lesion revealed EHE. The patient was started on local radiation therapy (RT). On follow-up, 3 months after the second surgery, the thoracic spinal pain had improved dramatically. Our review highlights the diagnosis, clinical presentation, and treatment of spinal EHE. Complete resection is associated with good outcome. Radiotherapy has been used in partially resected lesions. However, the role of radiotherapy as primary treatment is not yet defined. Further studies should develop a treatment algorithm for this rare tumour.

Marker Protein Expression Combined With Expression Heterogeneity is a Powerful Indicator of Malignancy in Acral Lentiginous Melanomas

PATIENTS AND METHODS

Samples of acral lentiginous melanomas (ALMs) were obtained from the Department of Pathology at Escola Paulista de Medicina-Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil. Demographic, clinical, and follow-up data were obtained from the charts of Hospital São Paulo. From 2 tissue microarrays containing 60 nevi and quadruplicate samples of ≥1.0-mm of 49 ALM, sections were stained to evaluate SCF, KIT, BRAF, CYCLIND1, MYC, and PTEN immunohistochemical protein expression.

RESULTS

Nevi and ALM from 2006 to 2010 were reviewed and collected. All specimens were in the vertical growth phase, and histopathological parameters indicated that tumors were at an advanced stage at diagnosis. Average tumor thickness was 6.95 mm, 63% were ulcerated, average mitotic index was 5 mitotic cells per mm, and 43% were at Clark's level V. Compared with nevi, the χ test showed that ALM significantly correlated with SCF protein expression (P = 0.001) and expression heterogeneity (P < 0.000). Similar findings were observed for KIT (P = 0.005, P = 0.003, respectively), MYC (P < 0.000, P < 0.000), and PTEN (P = 0.005, P < 0.000). Malignancy did not correlate with BRAF and CYCLIN D1 expression (P = 0.053 and P = 0.259, respectively), but it did significantly correlate with their heterogeneous expression (P < 0.000, P = 0.024, respectively). Combined protein expression had an odds ratio of greater malignancy when BRAF and MYC were positive and/or heterogeneously expressed (OR of 78 and 95, respectively).

DISCUSSION AND CONCLUSION

We show that marker protein expression, when combined with heterogeneous expression as shown by immunohistochemistry, is a powerful indicator of malignancy in ALMs, especially, when protein pairs are combined.

Diagnostic utility of epithelial and melanocitic markers with double sequential immunohistochemical staining in differentiating melanoma in situ from invasive melanoma

Identification of melanoma in situ and its distinction from invasive melanoma is important because of its significant impact on morbidity and mortality. However, this interpretation can cause pitfalls in the diagnosis even with the use of immunohistochemistry. The aim of this study is to evaluate the diagnostic utility of epithelial makers (AE1/AE3, CK5/6, and p63) combined with melanocytic markers (HMB-45, S-100, or Melan-A) using dual-color immunohistochemical staining, performed on a single slide by sequentially applying the antibodies. In this study, we show 4 cases in which examination of routine hematoxylin and eosin slides did not allow for clear-cut distinction between in situ and invasive melanoma and highlight the utility of the double-staining method. Therefore, we recommend this double-staining method with melanocytic and epithelial markers as a helpful adjunct to the diagnosis of cases with a differential diagnosis between in situ and invasive melanoma.

Anti-SIRP antibodies as a potential new tool for cancer immunotherapy

Tumor cells are thought to evade immune surveillance through interaction with immune cells. Much recent attention has focused on the modification of immune responses as a basis for new cancer treatments. SIRPα is an Ig superfamily protein that inhibits phagocytosis in macrophages upon interaction with its ligand CD47 expressed on the surface of target cells. Here, we show that SIRPα is highly expressed in human renal cell carcinoma and melanoma. Furthermore, an anti-SIRPα Ab that blocks the interaction with CD47 markedly suppressed tumor formation by renal cell carcinoma or melanoma cells in immunocompetent syngeneic mice. This inhibitory effect of the Ab appeared to be mediated by dual mechanisms: direct induction of Ab-dependent cellular phagocytosis of tumor cells by macrophages and blockade of CD47-SIRPα signaling that negatively regulates such phagocytosis. The antitumor effect of the Ab was greatly attenuated by selective depletion not only of macrophages but also of NK cells or CD8⁺ T cells. In addition, the anti-SIRPα Ab also enhances the inhibitory effects of Abs against CD20 and programmed cell death 1 (PD-1) on tumor formation in mice injected with SIRPα-nonexpressing tumor cells. Anti-SIRPα Abs thus warrant further study as a potential new therapy for a broad range of cancers.

Pseudomyogenic Hemangioendothelioma: A Vascular Tumor Previously Undescribed in the Oral Cavity

The pseudomyogenic hemangioendothelioma (PMH) is a low-grade malignant vascular neoplasm of different tissue planes including skin and soft tissue. Primary tumors in the skeletal muscle and bone have also been diagnosed. The PMH was introduced into the WHO classification of tumors of soft tissue and bone in 2013. This is the first description of oral involvement. A 21-year-old female presented with a 2-month old swelling of her gingiva. The swelling appeared red in color and was soft in consistency. A clinical diagnosis of a pyogenic granuloma was made and an incisional biopsy was submitted for histopathological evaluation. The lesion consisted of a proliferation of spindle and epithelioid looking cells. Cells were arranged in loose fascicles and sheets. Rhabdomyoblast-like cells were also seen. No mitotic figures were present. Lesional cells were reactive to cytokeratin AE1/AE3 and CD31. Lesional cell reactivity to S100 protein, HMB 45, SMA, Desmin and CD34 was negative. Following the diagnosis, a wide excision for clear margins was performed. No recurrence has been reported 2 years since the removal. The PMH is a cutaneous tumor that behaves in an indolent fashion. This is the first report of oral involvement by this neoplasm. Recognition of its histopathological features and immunohistochemical reactivity will prevent misadventures in the diagnosis of oral lesions.

Generation of metastatic melanoma specific antibodies by affinity purification

Melanoma is the most aggressive type of skin cancer and one of the most frequent tumours in young adults. Identification of primary tumours prone to develop metastasis is of paramount importance for further patient stratification. However, till today, no markers exist that are routinely used to predict melanoma progression. To ameliorate this problem, we generated antiserum directed against metastatic melanoma tissue lysate and applied a novel approach to purify the obtained serum via consecutive affinity chromatography steps. The established antibody, termed MHA-3, showed high reactivity against metastatic melanoma cell lines both in vitro and in vivo. We also tested MHA-3 on 227 melanoma patient samples and compared staining with the melanoma marker S100b. Importantly, MHA-3 was able to differentiate between metastatic and non-metastatic melanoma samples. By proteome analysis we identified 18 distinct antigens bound by MHA-3. Combined expression profiling of all identified proteins revealed a significant survival difference in melanoma patients. In conclusion, we developed a polyclonal antibody, which is able to detect metastatic melanoma on paraffin embedded sections. Hence, we propose that this antibody will represent a valuable additional tool for precise melanoma diagnosis.

Metastatic melanoma of the tongue: a case report with immunohistochemical profile

BACKGROUND

Melanoma of the skin is characterised by a high metastatic potential, but reports of metastasis to the tongue are rare. We report a case of skin melanoma with metastasis to the lymph nodes, tongue and brain.

OBJECTIVES

This report highlights the clinical and histological features of oral metastatic melanoma.

CASE REPORT

A 72-year-old man was seen with a nodule on the tongue. The differential diagnosis included salivary gland tumour, lymphoma and metastatic melanoma. His medical history revealed treatment for melanoma in the periumbilical region and micrometastases in the inguinal lymph nodes. An incisional biopsy was obtained and histological analysis showed the presence of a solid, epithelioid malignant tumour of monotonous appearance infiltrating the skeletal musculature. Immunohistochemistry showed reactivity of neoplastic cells to anti-HMB45, anti-melan A and anti-S100 antibodies and negativity for anti-PAN cytokeratin, confirming the diagnosis of metastatic melanoma.

CONCLUSION

The present findings highlight the importance of a complete medical evaluation of the patient by anamnesis to identify possible oral repercussions of primary diseases in other organs and/or systems.

Development and validation of a noninvasive 2-gene molecular assay for cutaneous melanoma

Background

Clinical and histopathologic assessment of pigmented skin lesions remains challenging even for experts. Differentiated and accurate noninvasive diagnostic modalities are highly desirable.

Objective

We sought to provide clinicians with such a tool.

Methods

A 2-gene classification method based on LINC00518 and preferentially expressed antigen in melanoma (PRAME) gene expression was evaluated and validated in 555 pigmented lesions (157 training and 398 validation samples) obtained noninvasively via adhesive patch biopsy. Results were compared with standard histopathologic assessment in lesions with a consensus diagnosis among 3 experienced dermatopathologists.

Results

In 398 validation samples (87 melanomas and 311 nonmelanomas), LINC00518 and/or PRAME detection appropriately differentiated melanoma from nonmelanoma samples with a sensitivity of 91% and a specificity of 69%. We established LINC00518 and PRAME in both adhesive patch melanoma samples and underlying formalin fixed paraffin embedded (FFPE) samples of surgically excised primary melanomas and in melanoma lymph node metastases.

Limitations

This technology cannot be used on mucous membranes, palms of hands, and soles of feet.

Conclusions

This noninvasive 2-gene pigmented lesion assay classifies pigmented lesions into melanoma and nonmelanoma groups and may serve as a tool to help with diagnostic challenges that may be inherently linked to the visual image and pattern recognition approach.

A case of S-100 negative melanoma: A diagnostic pitfall in the workup of a poorly differentiated metastatic tumor of unknown origin

When confronted with a metastatic poorly differentiated tumor of unknown origin, the initial workup includes the standard panel of immunostains to rule out carcinoma, sarcoma, lymphoma, and the greatest mimicker in pathology - malignant melanoma. Although not specific, the S-100 protein is expressed in over 95% of malignant melanomas. Herein, we present a case of multiorgan metastatic malignancy with a dominant hilar and mediastinal mass in a current smoker; clinically, highly suggestive of widespread primary lung cancer. This case was eventually classified as malignant melanoma, despite a significant diagnostic challenge due to lack of prior history, unusual cytomorphology, and S-100 protein negativity. A battery of immunostains was performed and the addition of other melanocytic-associated markers confirmed the melanocytic lineage of the neoplasm. This case highlights the pitfalls in the differential diagnosis of a metastatic tumor of unknown origin by fine needle aspiration cytology due to the significant morphologic overlap of poorly differentiated malignancies. We emphasize that, albeit rare, malignant melanomas can be completely negative for S-100 protein and the use of additional melanocytic-associated markers in the differential workup maybe critical in arriving promptly at a proper diagnosis. We also briefly discuss other currently available immunohistochemical markers that can assist in the identification of the S-100 negative melanoma.

Natural products from aquatic eukaryotic microorganisms for cancer therapy: Perspectives on anti-tumour properties of ciliate bioactive molecules

Several modern drugs, including those for cancer therapy, have been isolated from natural sources, are based on natural products and its derivatives, or mime natural products. Some of them are in clinical use, others in clinical trials. The success of natural products in drug discovery is related to their biochemical characteristics and to the technologic methods used to study their feature. Natural compounds may acts as chemo-preventive agents and as factors that increase therapeutic efficacy of existing drugs, thus overcoming cancer cell drug resistance that is the main factor determining the failure in conventional chemotherapy. Water environment, because of its physical and chemical conditions, shows an extraordinary collection of natural biological substances with an extensive structural and functional diversity. The isolation of bioactive molecules has been reported from a great variety of aquatic organisms; however, the therapeutic application of molecules from eukaryotic microorganisms remains inadequately investigated and underexploited on a systematic basis. Herein we describe the biological activities in mammalian cells of selected substances isolated from ciliates, free-living protozoa common almost everywhere there is water, focusing on their anti-tumour actions and their possible therapeutic activity. In particular, we unveil the cellular and molecular machine mediating the effects of cell type-specific signalling protein pheromone Er-1 and secondary metabolites, i.e. euplotin C and climacostol, in cancer cells. To support the feasibility of climacostol-based approaches, we also present novel findings and report additional mechanisms of action using both in vitro and in vivo models of mouse melanomas, with the scope of highlighting new frontiers that can be explored also in a therapeutic perspective. The high skeletal chemical difference of ciliate compounds, their sustainability and availability, also through the use of new organic synthesis/modifications processes, and the results obtained so far in biological studies provide a rationale to consider some of them a potential resource for the design of new anti-cancer drugs.

Selected benign cutaneous lesions that may simulate melanoma histologically

As cutaneous melanomas manifest a wide spectrum of clinical and pathologic presentations, several other lesions enter into their differential diagnosis. This article considers those entities, including melanocytic hyperplasia, cellular nodules in congenital nevi, atypical lentiginous melanocytic proliferations, "special site" nevi, epithelioid histiocytoma, neurothekeoma, cellular schwannoma, and proliferating scars.

Cellular Blue Nevus Diagnosed following Excision of Melanoma: A Challenge in Diagnosis

A case of a 41-year-old woman with a history of nodular melanoma (NM), associated with an indurated dome-shaped blue-black nodule with a diameter of 1.2 cm in the gluteal region, is presented. Clinical diagnosis of the lesion, present from birth, was blue nevus. Recently, the nodule has been showing a mild enlargement and thus complete resection was performed. Histological analysis revealed a pigmented lesion with an expansive pattern of extension into the dermis and the subcutaneous adipose tissue. The lesion displayed an alveolar pattern as well as a pigmented dendritic cell pattern. The histology was consistent with cellular blue nevus (CBN); however, the history of NM which was excised one year earlier, as well as the clinical information about the slow growing lesion, included a differential diagnosis of CBN, borderline melanocytic tumor, and malignant blue nevus. Additional immunohistochemical (HMB-45, p16, and Ki-67) and molecular (BRAF V600E mutation) analyses were performed on both lesions: the CBN-like and the previously excised NM. Along with lesion history and histological analyses, p16 staining and BRAF were useful diagnostic tools for confirming the benign nature of CBN in this case.

Dermoscopic and Immunohistochemical Changes in Acquired Melanocytic Nevi following Narrow-Band Ultraviolet B Therapy

BACKGROUND

Acquired melanocytic nevi (AMN) have been reported to undergo morphological and dermoscopic changes following exposure to narrow-band ultraviolet B (NB-UVB) radiation.

OBJECTIVE

To study the morphological, dermoscopic and immunohistochemical changes in AMN following NB-UVB radiation.

METHODS

Suberythemogenic NB-UVB sessions were delivered to 40 patients with AMN. For each patient, a minimum of 2 nevi were selected. One nevus was surgically removed from each patient prior to sessions as control; for the other nevus, dermoscopic images were captured before and after NB-UVB sessions. The images were evaluated for changes. At the end, another nevus was surgically removed for immunohistochemical assessment of Ki-67 and melan-A.

RESULTS

Our study showed a statistically significant increase in the size of AMN following NB-UVB radiation. Benign dermoscopic changes were observed. Statistically significant positive correlations were found between some dermoscopic findings and the total cumulative dose of NB-UVB. Immunohistochemical analysis did not show any significant change in the exposed AMN.

CONCLUSION

AMN irradiated with repeated suberythemogenic doses of NB-UVB showed benign morphological and dermoscopic changes, and this was confirmed by our immunohistochemical study.

Metastatic melanoma: Pathologic characterization, current treatment, and complications of therapy

Metastatic melanoma (MM) has the potential to involve virtually any anatomical site, and it also has a wide spectrum of histological appearances. General clinicopathologic data pertaining to MM are presented in this review, together with a discussion of its differential diagnosis and therapy. "Biological" agents used in the treatment of melanoma are considered, along with the pathological features of the complications that they may cause.

[Malignant head and neck melanoma : Part 1: Diagnosis and histological particularities]

About 15% of all cutaneous melanomas develop in the head and neck region. Mucosal melanomas are rare and represent only 1% of all melanomas, however, most frequently, these are located in the nose, the paranasal sinuses and the oral cavity. Visual diagnosis and reflected-light microscopy are relevant for the evaluation of melanoma-suspect lesions. Histological investigation of resected tumors need special skills of the histopathologist and includes in case of high-risk tumors investigations of mutations in the tumor tissue concerning NRAS, BRAF and KIT. The risk of lymphatic or hematogeneous spread rises with increasing tumor thickness and the presence of further prognostic risk factors such as ulceration of the primary tumor or the presence of mitoses within the tumor.

Adrenal malignant melanoma masquerading as a pheochromocytoma in a patient with a history of a multifocal papillary and medullary thyroid carcinoma

OBJECTIVE

Adrenal masses usually represent benign and nonfunctional adrenal adenomas; however, primary or metastatic malignancy should also be considered. Discovery of an adrenal mass needs further evaluation in order to exclude malignancy and hormonal secretion. We present a rare case of a possibly primary adrenal malignant melanoma with imaging and biochemical features of a pheochromocytoma.

CASE REPORT

A 61-year-old male farmer was referred for evaluation of a mass in the right supraclavicular region and a left adrenal lesion. The patient had a history of a multifocal papillary and medullary thyroid carcinoma. Laboratory tests revealed increased 24hour urinary dopamine and also increased serum calcitonin and neuron specific enolase. A pathology report of the resected right supraclavicular mass and left adrenal showed a malignant melanoma.

CONCLUSION

This is a case of a possibly primary adrenal malignant melanoma with imaging and biochemical features of a pheochromocytoma. Although this case is very rare and there are rigid diagnostic criteria for the diagnosis of primary adrenal melanoma, it underlines the fact that the differential diagnosis of a dopamine secreting adrenal mass should include primary or metastatic malignant melanoma in order to determine the best diagnostic approach for the patient and select the most appropriate surgical management.