Unusual variants of malignant melanoma

Desmoplastic Melanoma of the Chest Wall: a Diagnostic Dilemma

Desmoplastic melanoma is an extremely rare subtype of malignant melanoma comprising only 1% of all the cutaneous melanomas. Being amelanotic and owing to its histopathological features of spindle cells lying in a collagenized stroma, it is often misdiagnosed as a dermatofibroma or scar tissue. The present case study describes a case of desmoplastic melanoma of the chest wall where the final diagnosis could be arrived at only after an extensive immunohistochemical panel to exclude other spindle cell proliferations.

Partially Dedifferentiated Primitive Malignant Melanoma with Pseudo-Angiomatous Features: A Case Report with Review of the Literature

Malignant melanoma (MM) is traditionally known as the "great mime" of human pathology, as it is potentially capable of imitating the most disparate neoplasms. It is known that in addition to the more classic histotypes of MM, there are also rare forms, including angiomatoid MM. Similarly, it has been amply demonstrated in the literature that MM is capable of dedifferentiating, losing melanocytic lineage markers, constituting a diagnostic challenge for the pathologist. Although 5 cases of primary angiomatoid MM have been described in the literature, to the best of our knowledge, no cases of dedifferentiated melanoma with pseudo-angiomatoid aspects have ever been described. In this paper, we present a very rare case of partially dedifferentiated MM in which the most dedifferentiated component lost melanocytic lineage immunohistochemical markers and assumed a pseudo-angiomatous morphology. Given the rarity of the case, we carried out a literature review of similar cases described, trying to draw new future perspectives not only about this particular variant of MM but also about the widest field of dedifferentiation/undifferentiation of MM.

Pitfalls in Cutaneous Melanoma Diagnosis and the Need for New Reliable Markers

Cutaneous melanoma is one of the most aggressive forms of skin cancer, with the development of advanced stage disease resulting in a high rate of patient mortality. Accurate diagnosis of melanoma at an early stage is essential to improve patient outcomes, as this enables treatment before the cancer has metastasised. Histopathologic analysis is the current gold standard for melanoma diagnosis, but this can be subjective due to discordance in interpreting the morphological heterogeneity in melanoma and other skin lesions. Immunohistochemistry (IHC) is sometimes employed as an adjunct to conventional histology, but it remains occasionally difficult to distinguish some benign melanocytic lesions and melanoma. Importantly, the complex morphology and lack of specific biomarkers that identify key elements of melanoma pathogenesis can make an accurate confirmation of diagnosis challenging. We review the diagnostic constraints of melanoma heterogeneity and discuss issues with interpreting routine histology and problems with current melanoma markers. Innovative approaches are required to find effective biomarkers to enhance patient management.

Carbon ion radiotherapy with complete tumor regression for primary malignant melanoma of female urethra orifice: a case report

Primary malignant melanoma of the female urethra (PMMFU) is extremely rare, accounting for 0.2% of all melanomas, and fewer than 200 cases have been reported worldwide. Because of the small number of clinical cases and unclear biological characteristics, there is no uniform and standard treatment protocol. We herein describe the treatment of PMMFU using carbon ion radiotherapy. The radiotherapy was delivered at 60.8 Gy (RBE) in 16 fractions, once daily, five times per week. The patient achieved complete tumor disappearance within 1 year after carbon ion radiotherapy and remained disease-free thereafter. She developed acute grade 1 radiation dermatitis and urethritis, which resolved quickly; no other toxic effects were observed. At the time of this writing, her survival duration was 33 months. This case demonstrates that carbon ion radiotherapy may be a good option for primary genitourinary mucosal malignancies.

Uncommon Histopathological Variants of Malignant Melanoma. Part 2

Despite new horizons opened by recent advances in molecular pathology, histological evaluation still remains the diagnostic gold standard regarding cutaneous melanocytic neoplasms. Several histological variants of melanoma have been described, and their knowledge is crucial for accurate diagnosis and classification of cases with unusual clinico-pathological features. Uncommon histological variants of melanoma have been described based on a broad constellation of features, including architectural pattern, stromal alterations, cytological attributes, and other morphological properties. This review is aimed at providing an extensive discussion of unusual but distinctive histopathological variants of melanoma.

Spitzoid cutaneous melanoma is associated with favorable clinicopathological factors and outcome

BACKGROUND

Spitzoid melanoma is one of the rare subtypes of melanoma, whose clinical and pathological characteristics have yet to be understood.

OBJECTIVE

Understanding the histopathologic features and behavior characteristics of Spitzoid cutaneous melanoma.

METHODS

A total number of 11 Turkish Caucasian patients with pathologically diagnosed Spitzoid melanoma were analyzed retrospectively.

RESULTS

The median age of patients was 24 years (ranging from 16 to 54 years), and the females outnumbered the males (90%). The extremities, especially lower limbs (67%), were the most commonly affected primary areas (64% of patients). Median depth and mitotic rate were 2.2 mm and 3 /mm² , respectively. The presence of ulceration and regression were observed in a few lesions (14%). While tumor-infiltrating lymphocytes were expressed in all of the lesions, none of the lesions was associated with lymphovascular invasion and/or neurotropism. The regional lymph nodes were involved only in minority of the patients (27%), and no patients had metastatic disease. Recurrences occurred in only two patients (18%) that affected merely distant areas, that is, lung and brain. The median disease-free survival time and 5-year disease-free survival rate were 20.5 months and 80.6%, respectively. Only one (9%) death occurred; and the median overall survival time was 26.2 months, and 5-year overall survival rate was 90.7%.

CONCLUSION

Spitzoid cutaneous melanoma is correlated with favorable histopathologic and clinical characteristics, and therefore, it is associated with better survival rates.

Uncommon Histopathological Variants of Malignant Melanoma: Part 1

Despite new horizons opened by recent advances in molecular pathology, histological evaluation still remains the diagnostic gold standard regarding cutaneous melanocytic neoplasms. Several histological variants of melanoma have been described, and their knowledge is crucial for accurate diagnosis and classification of cases with unusual clinicopathological features. Uncommon histological variants of melanoma have been described based on a broad constellation of features, including architectural pattern, stromal alterations, cytological attributes, and other morphological properties. This review is aimed at providing an extensive discussion of unusual but distinctive histopathological variants of melanoma.

Oncocytic Melanoma: A Study of a Rare Entity

The authors report the second case of oncocytic melanoma, one of the rarest known melanoma variants. The diagnosis was established by Fontana stain positivity, expression of S100 protein as well as gp100/HMB45, and demonstration of numerous mitochondria by ultrastructure. Because it is known that some oncocytic tumors of the thyroid gland and kidney contain point mutations and common deletions of mitochondrial DNA, the complete mitochondrial DNA of the reported oncocytic melanoma was also studied. It was normal except for 2 private separate point mutations, predicted to be not pathogenic, which do not seem to play any role in the tumor phenotype.

Blue Nevus-Like Metastasis of a Cutaneous Melanoma Identified by Fluorescence In Situ Hybridization

A blue nevus-like melanoma is a rare melanoma variant arising from or histologically similar to a blue nevus. It can be challenging to distinguish a cellular blue nevus from a blue nevus-like melanoma, particularly in cases of blue nevus-like melanoma lacking a transition from a clearly benign component. We present a case of a 78-year-old man who refused treatment for a previously existing melanoma and subsequently developed a gray nodule near the site of the previous melanoma. After fluorescence in situ hybridization revealed copy number gains in RREB1, this was diagnosed as a blue nevus-like metastatic melanoma. Blue nevus-like metastatic melanoma is most commonly seen near the site of the primary cutaneous melanoma. This entity should be considered in a patient with a history of melanoma and a new blue nevus-like lesion.

An unusual case of desmoplastic malignant melanoma

Desmoplastic malignant melanoma is a rare variant of spindle cell melanoma, commonly seen in older adults, on sun-exposed areas. It accounts for 1-4% of all cases of cutaneous melanoma. The common location of the desmoplastic melanoma is the head and neck region, whereas, other sites are less common. Regional lymph node involvement is reported in 0 to 13.7% of the cases, which is less frequent than other cutaneous melanomas. A 75-year-old male presented with an ulceroproliferative growth on the left foot that was diagnosed as desmoplastic melanoma with regional lymph node metastasis and in transit metastasis, with extensive pulmonary metastasis.

A case of spitzoid melanoma

Spitzoid melanoma is a subtype of melanoma that, clinically and histologically, resembles a Spitz nevus. Clinically, spitzoid melanomas usually evolve from amelanotic nodular lesions, growing to 1 cm or more in diameter. They often remain clinically undiagnosed because of their wide variety of clinical appearances and a lack of pigmentation. Distinguishing a Spitz nevus from a spitzoid melanoma can be extremely difficult. Features that favor the diagnosis of a spitzoid melanoma are asymmetrical shape, diameter greater than 1 cm, a lesion with a deep invasive component, and a high degree of cytologic atypia. There have been only rare reports in the literature of the presence of giant cells in malignant melanoma, and the presence of these cells may result in its misdiagnosis as a histiocytic tumor. We present a case of spitzoid melanoma on the right ankle of a 22-year-old-woman.

Curcumin does not switch melanin synthesis towards pheomelanin in B16F10 cells

Melanin, the basic skin pigment present also in the majority of melanomas, has a huge impact on the efficiency of photodynamic, radio- or chemotherapies of melanoma. Moreover, the melanoma cells produce more melanin than normal melanocytes in adjacent skin do. Thus, attention has been paid to natural agents that are safe and effective in suppression of melanogenesis. B16F10 cells were studied by electron paramagnetic resonance (EPR) spectroscopy. The cells were cultured for 24-72 h in RPMI or DMEM with or without curcumin. The results confirmed that curcumin has no significant effect on B16F10 cells viability at concentrations of 1-10 µM. Curcumin at concentration of 10 µM significantly inhibited their proliferation and stimulated differentiation. We have not stimulated melanogenesis hormonally but we found a strong increase in melanogenesis in DMEM, containing more L-Tyr, as compared to RPMI. The EPR studies revealed that the effect of curcumin on melanogenesis in RPMI-incubated cells was not significant, and only in DMEM was curcumin able to inhibit melanogenesis. The effect of curcumin was only quantitative, as it did not switch eumelanogenesis towards pheomelanogenesis under any conditions. Interestingly, we observed elevation of production of hydrogen peroxide in DMEM-incubated cells, in parallel to the facilitation of melanogenesis. Curcumin significantly but transiently intensified the already pronounced generation of H2O2 in DMEM. We conclude that the quantitative effect of curcumin on melanogenesis in melanoma is intricate. It depends on the basic melanogenetic efficiency of the cells, and can be observed only in strongly pigmented cells. Qualitatively, curcumin does not switch melanogenesis towards pheomelanogenesis, either in strongly, or in weakly melanized melanoma cells.

Atypical Spitzoid neoplasms: a review of potential markers of biological behavior including sentinel node biopsy

Atypical cutaneous melanocytic lesions, including those with Spitzoid features, can be difficult to categorize as benign or malignant. This can lead to suboptimal management, with potential adverse patient outcomes. Recent studies have enhanced knowledge of the molecular and genetic biology of these lesions and, combined with clinicopathological findings, is further defining their biological spectrum, classification, and behavior. Sentinel node biopsy provides important prognostic information in patients with cutaneous melanoma, but its role in the management of melanocytic lesions of uncertain malignant potential (MELTUMP) is controversial. This paper examines the role of molecular testing and sentinel node biopsy in MELTUMPs, particularly atypical Spitzoid tumors.

Junctional spitz tumor (nevus) of the upper lip

Spitz tumor (nevus) is a rare, melanocytic lesion that primarily affects children and adolescents. The lesion may share many clinical and histological similarities with malignant melanoma and careful microscopic examination is required to render the proper diagnosis. Complete excision with close follow-up is considered the appropriate treatment. Despite the common presentation of Spitz nevi on the facial skin, lip involvement has only rarely been described in the English language literature. In the present study, a case of Spitz tumor located on the vermilion border of the upper lip in a 16-year old female patient is reported.

Sentinel lymph node metastasis is not predictive of poor outcome in patients with problematic spitzoid melanocytic tumors

The diagnosis and clinical management of spitzoid melanocytic tumors with atypical features remain problematic and controversial. In the past decade, sentinel lymph node mapping has been advocated as a diagnostic test in this setting to discriminate melanoma from benign tumors. Recent studies, however, consistently show that despite the presence of lymph node metastases these patients almost always fare well. We investigated the outcome of patients with atypical Spitz tumors and spitzoid melanoma who received sentinel lymph node mapping to clarify current recommendations in managing patients with these diagnostically challenging tumors. A search of the electronic files of the Massachusetts General Hospital Pathology Service identified 41 patients treated with sentinel lymph node biopsy for atypical Spitz tumor or spitzoid melanoma from 1998 to 2008. These patients included 23 patients with atypical Spitz tumors and 17 patients with spitzoid melanoma. Sentinel lymph nodes were positive in 26% of patients with atypical Spitz tumors (6/23) and 35% with spitzoid melanomas (6/17). One patient with spitzoid melanoma developed in-transit metastasis; 0 of 40 patients developed metastases beyond the regional lymph node basin with a mean follow-up of 57 months. Sentinel lymph node biopsy may not be a reliable prognostic discriminatory test in patients with atypical Spitz tumors. Patients with spitzoid melanomas and positive sentinel lymph nodes have a more indolent course than those with bona fide conventional melanoma and positive sentinel nodes.

Oral atypical cellular blue nevus: an infiltrative melanocytic proliferation

The atypical cellular blue nevus is an extremely rare nevomelanocytic lesion which lacks precise histologic characterization in the current literature. Given the potential for significant architectural and cytologic overlap with melanoma, further study, including molecular analysis, is needed. This is the first description of an atypical cellular blue nevus of the oral cavity.

RACK1, a clue to the diagnosis of cutaneous melanomas in horses

Background

Melanocytic proliferations are common in horses but the diagnosis of malignancy is not always straightforward. To improve diagnosis and prognosis, markers of malignancy are needed. Receptor for activated C kinase 1 (RACK1) protein may be such a marker. RACK1 was originally found to characterize malignant melanocytic lesions in the Melanoblastoma-bearing Libechov minipig (MeLiM) and, later, in human patients. Our purpose was to investigate the value of RACK1 in the classification of cutaneous melanocytic proliferations in horses.

Results

Using immunofluorescence, we report here that both MITF (Microphthalmia-associated transcription factor) and PAX3 (Paired box 3) allow the identification of melanocytic cells in horse skin samples. Importantly, RACK1 was detected in melanocytic lesions but not in healthy skin melanocytes. Finally, we found that RACK1 labeling can be used in horses to distinguish benign melanocytic tumors from melanomas. Indeed, RACK1 labeling appeared more informative to assess malignancy than individual histomorphological features.

Conclusions

This study confirms that horses provide an interesting model for melanoma genesis studies. It establishes MITF and PAX3 as markers of horse melanocytic cells. RACK1 emerges as an important marker of malignancy which may contribute to progress in the diagnosis of melanomas in both human and veterinary medicine.

The pathology of melanoma

Although melanoma represents only 10% of all skin cancer diagnoses, it accounts for at least 65% of all skin cancer-related deaths. The number of new cutaneous melanoma cases projected during 2010 was 68,000-a 23% increase from the 2004 prediction of 55,100 cases. In 2015, the lifetime risk of developing melanoma is estimated to increase to 1 in 50. As the incidence of melanoma continues to rise, now more than ever, clinicians and histopathologists must have familiarity with the various clinical and pathologic features of cutaneous melanoma.

A case of spitzoid melanoma with lymph node metastasis in a child

The distinction of a spitz nevus from a melanoma can be difficult and in some cases, impossible. A misdiagnosed spitz nevus can metastasize and lead to fatal outcomes, especially in children. A 5-yr-old girl presented with a 1-yr history of a solitary pinkish nodule on her left hand. On physical examination, she had a palpable left axillary lymph node. We performed biopsy and checked 3 sentinel lymph nodes (SLN) on her axillary area. The biopsy specimen showed multiple variably sized and shaped nests with large spindle or polygonal cells and SLN biopsy showed 3 of 3 lymph nodes that were metastasized. Under the diagnosis of spitzoid melanoma, she was treated with excision biopsy and complete left axillary lymph nodes were dissected. She received interferon-α2b subcutaneously at a dose of 8 MIU per day, 3 times weekly for 12 months, and shows no recurrence.

Spitz nevi and other Spitzoid lesions part I. Background and diagnoses

Spitz nevi are melanocytic proliferations that are characterized by spindled and/or epithelioid nevomelanocytes. First interpreted as juvenile melanoma, these lesions were later characterized as benign and were observed to affect all age groups. Today, contrasting opinions persist regarding the fundamental benignancy versus malignancy within the spectrum of Spitz tumors. Beyond clinical outcome, this controversy has also been fueled by complex and sometimes convoluted classification schemes based on pathologic characteristics. More recently, immunophenotypic and molecular analyses have begun to clarify the etiologic nature of these tumors. Recent evidence suggests that histopathologic features that suggest more aggressiveness in Spitz tumors relate to mitoses and inflammation.

Multiple bilateral ocular metastases from malignant melanoma associated with blue nevi

PURPOSE

Malignant melanoma associated with a blue nevus is a rare diagnosis. Additionally, only a handful of cases of malignant melanoma associated with blue nevi involving the ocular structures have been reported. We report a probable case of malignant melanoma associated with a blue nevus with metastasis to multiple bilateral ocular structures.

METHODS

Observational case report.

RESULTS

We report a case of a 27-year-old man with lymph node biopsy-proven malignant melanoma as well as a separate skin biopsy of a blue nevus, who developed multiple bilateral pigmented ocular lesions on the sclera, iris, trabecular meshwork, and choroid.

CONCLUSIONS

Although ocular histopathologic evidence could not be obtained, our case likely represents a case of explosive widespread metastasis probably originating from a blue nevus of unknown location, which involved both eyes and adnexae.

Perineural extension of cutaneous desmoplastic melanoma mimicking an intracranial malignant peripheral nerve sheath tumor

The authors present a case illustrating the importance of obtaining a biopsy of any facial skin lesions in a patient presenting with an intracranial tumor involving the facial or trigeminal nerve. Conventional malignant melanoma metastasizes to the brain frequently and does not usually pose diagnostic difficulties. Direct intracranial spread of cutaneous melanoma is rare. In our patient, desmoplastic melanoma with perineural spread to the Meckel cave mimicked a malignant peripheral nerve sheath tumor clinically, radiographically, and histologically.

Melanoma in children

CONTEXT

Cutaneous melanoma in childhood (CMC) is rare; therefore, its prognostic factors and biologic behavior, and the effectiveness of adjuvant techniques for CMC remain mostly unknown.

OBJECTIVE

To review the most useful, evidence-based practice criteria for establishing the diagnosis of CMC, for which universally accepted criteria are lacking, in order to facilitate the interpretation and comparison of the results from different institutions, and to perform systematic reviews and meta-analysis.

DATA SOURCES

A comprehensive review of the most relevant previous single-institution series reported in the literature since 1990, including our cumulative experience of 137 cases of primary cutaneous and mucosal melanoma in patients younger than 18 years. Special characteristics of melanoma in children are discussed, regarding clinical settings and risk factors, helpful histologic features, and immunohistochemical patterns for diagnosis and prognosis.

CONCLUSIONS

Careful analysis of histologic features as well as the additional information provided by immunohistochemistry should allow for a correct diagnosis in most cases of melanoma in children. Although it seems that pediatric patients with melanoma have higher survival probability than adults, still a number of children will develop metastasis and die of their disease, particularly when melanoma is diagnosed after puberty. Until further studies more accurately determine the prognosis, a prudent approach to CMC diagnosis and therapy seems to follow the same principles as those established for adult melanoma.

Functional and clinical relevance of chondroitin sulfate proteoglycan 4

The lack of effective conventional therapies for the treatment of advanced stage melanoma has stimulated interest in the development of novel strategies for the management of patients with malignant melanoma. Among them, immunotherapy has attracted much attention because of the potential role played by immunological events in the clinical course of melanoma. For many years, T cell-based immunotherapy has been emphasized in part because of the disappointing results of the monoclonal antibody (mAb)-based clinical trials conducted in the early 1980s and in part because of the postulated major role played by T cells in tumor growth control. More recently, mAb-based therapies have gained in popularity given their clinical and commercial success for a variety of malignant diseases. As a result, there has been increased interest in identifying and characterizing antibody-defined melanoma antigens. Among them, the chondroitin sulfate proteoglycan 4 (CSPG4), also known as high molecular weight-melanoma associated antigen (HMW-MAA) or melanoma chondroitin sulfate proteoglycan (MCSP), has attracted much attention in recent years because of the growing experimental evidence that it fulfills two requirements for immunotherapy to be therapeutically effective: (1) targeting of cancer stem cells (CSC) and (2) development of combinatorial therapies to counteract the escape mechanisms driven by the genetic instability of tumor cells. With this in mind, in this chapter, we have reviewed recent information related to the distribution of CSPG4 on various types of tumors, including CSC, its expression on pericytes in the tumor microenvironment, its recognition by T cells, its role in cell biology as well as the potential mechanisms underlying the ability of CSPG4-specific immunity to control malignant cell growth.

The air liquid-interface, a skin microenvironment, promotes growth of melanoma cells, but not their apoptosis and invasion, through activation of mitogen-activated protein kinase

The air-liquid interface (ALI) is a common microenvironment of the skin, but it is unknown whether the ALI affects melanoma cell behaviors. Using a collagen gel invasion assay, immunohistochemistry, and Western blots, here we show that melanoma cell proliferation in cultures with an ALI is higher than melanoma cell proliferation in submerged cultures. Bromodeoxyuridine (BrdU) uptake, an indicator of cell proliferation, of melanoma cells at the ALI was about 3 times that of submerged cells, while ALI and submerged melanoma cells had similar levels of single-stranded DNA (a marker of apoptosis). The ALI enhanced the expression of Raf-1, MEK-1 and pERK-1/2 components of the mitogen-activated protein kinase (MAPK) cascade, in cells more than the submerged condition did. The increases in BrdU uptake and pERK-1/2 expression promoted by ALI was abolished by the MEK inhibitor, PD-98059. ALI-treated and submerged melanoma cells did not infiltrate into the collagen gel, and they showed no significant difference in the expression of the invasion- and motility-related molecules, matrix metalloproteinase-1 and -9, laminin 5, and filamin A. Our data indicate that the ALI, a skin microenvironment, accelerates the growth, but not the apoptosis or invasion, of melanoma cells through MAPK activation.