[The role of new molecular tests in the diagnosis of melanoma in a setting of congenital nævus in an infant]. / Apport des nouveaux tests moléculaires dans le diagnostic d'un mélanome sur nævus congénital chez un nourrisson.

INTRODUCTION: Congenital and infantile melanomas are extremely rare. We report a case of a child presenting at birth with a giant congenital nevus complicated by melanoma and on long-term follow-up with exploration using new immunohistochemistry and molecular biology tools. OBSERVATION: A new-born girl presented at birth with a large congenital cervico-mandibular tumour with para-pharyngeal extension and underlying osteolysis. At 7 months, histology and immunohistochemistry of the operative specimen revealed nodules with atypical features (mitotic figures, necrosis and positive expression of KI67 and P53 in approximatively 50 % of the melanocytic nuclei). A diagnosis was made of infantile melanoma associated with congenital nevi. Repeated surgery and monitoring (clinical and imaging) were performed. At the age of 7 years, as there was no evidence of metastatic lesions, further analyses were performed on the initial operative specimen. Investigation of transcription factor expression using immunohistochemistry, comparative genomic hybridization and histology-guided mass spectrometry, although suspect, did not in itself support a diagnosis of melanoma. Finally, at the age of 7 years, hepatic and pulmonary metastases were reported. Despite combined immunotherapy with ipilimumab and nivolumab, the child died 5 months later. CONCLUSION: This case illustrates the complexity of diagnosis of infantile melanoma and the risk of metastatic involvement long after the initial diagnosis. Diagnosis may be difficult and necessitates expert advice and the application of several recent methods to reach a conclusion and initiate appropriate treatment.

HSP90 as a marker of progression in melanoma.

BACKGROUND: HSP90 chaperones molecules critical for cell survival and malignant progression, including mutated B-raf. HSP90-targeting agents are in clinical trials. No large studies have been conducted on expression of HSP90 in melanomas. MATERIALS AND METHODS: Tissue microarrays containing 414 nevi, 198 primary and 270 metastatic melanomas were assessed using our automated quantitative analysis (AQUA) method of in situ protein measurement; we use S-100 to define pixels as melanocytes (tumor mask) within the array spot, and measure HSP90 expression within the mask using Cy5-conjugated antibodies. RESULTS: HSP90 expression was higher in melanomas than nevi (P < 0.0001) and higher in metastatic than primary specimens (P < 0.0001). No association was seen between high HSP90 expression and survival in the primary or metastatic patient subsets. In primary melanomas, high HSP90 expression was associated with higher Clark level (P = 0.0167) and increased Breslow depth (P < 0.0001). CONCLUSIONS: HSP90 expression was significantly higher in tumors than nevi and was associated with disease progression, indicating that it might be a valuable drug target in melanoma, as well as a useful diagnostic marker. Prospective studies are needed to confirm the diagnostic role of HSP90, as well as the predictive role of HSP90 expression in patients treated with HSP90 inhibitors.

Speckled lentiginous nevus: within the spectrum of congenital melanocytic nevi.

BACKGROUND: Currently, there is disagreement as to whether speckled lentiginous nevi (nevi spili) are congenital or acquired pigmented lesions. Part of this controversy is related to the natural history of these lesions that often present at birth as hyperpigmented patches and then take several years to reach their more readily recognized spotted form. Arguments in favor of speckled lentiginous nevi as a subtype of congenital nevi include the following observations: multiple reports of lesions present at birth or noted soon thereafter; patterns of distribution reflecting embryonic development; hamartomatous behavior with various types of nevi (eg, junctional nevi, blue nevi, and Spitz nevi) presenting in the same lesion over time; and histologic features of congenital melanocytic nevi within the spots. Herein we present additional evidence for the congenital nature of speckled lentiginous nevi. OBSERVATIONS: Ten patients are described with congenital pigmented lesions that had the clinical appearance of speckled lentiginous nevi in whole or in part. These lesions either evolved and acquired an appearance more suggestive of "classic" congenital nevi, or they existed as "hybrid" lesions with portions appearing as classic congenital nevi adjacent to or admixed with portions appearing as speckled lentiginous nevi. On histologic examination, biopsy specimens from the spots within these lesions showed features of congenital melanocytic nevi. CONCLUSIONS: These 10 cases, along with the arguments outlined above, provide strong support for the hypothesis that speckled lentiginous nevi are a subtype of congenital melanocytic nevi.

Under the microscope. Surgeons, pathologists, and melanocytic nevi.

Predicting the biologic behavior of melanocytic neoplasms (benign versus malignant) based on histology is one of the most difficult challenges in surgical pathology and dermatology. Success in the field of melanocytic neoplasia can be achieved by two means: performing excisions or biopsies that maximize the obtainable histologic information and providing sufficient history.

Genetic inactivation or pharmacological inhibition of Pdk1 delays development and inhibits metastasis of Braf(V600E)::Pten(-/-) melanoma.

Phosphoinositide-dependent kinase-1 (PDK1) is a serine/threonine protein kinase that phosphorylates members of the conserved AGC kinase superfamily, including AKT and protein kinase C (PKC), and is implicated in important cellular processes including survival, metabolism and tumorigenesis. In large cohorts of nevi and melanoma samples, PDK1 expression was significantly higher in primary melanoma, compared with nevi, and was further increased in metastatic melanoma. PDK1 expression suffices for its activity, owing to auto-activation, or elevated phosphorylation by phosphoinositide 3'-OH-kinase (PI3K). Selective inactivation of Pdk1 in the melanocytes of Braf(V600E)::Pten(-/-) or Braf(V600E)::Cdkn2a(-/-)::Pten(-/-) mice delayed the development of pigmented lesions and melanoma induced by systemic or local administration of 4-hydroxytamoxifen. Melanoma invasion and metastasis were significantly reduced or completely prevented by Pdk1 deletion. Administration of the PDK1 inhibitor GSK2334470 (PDKi) effectively delayed melanomagenesis and metastasis in Braf(V600E)::Pten(-/-) mice. Pdk1(-/-) melanomas exhibit a marked decrease in the activity of AKT, P70S6K and PKC. Notably, PDKi was as effective in inhibiting AGC kinases and colony forming efficiency of melanoma with Pten wild-type (WT) genotypes. Gene expression analyses identified Pdk1-dependent changes in FOXO3a-regulated genes, and inhibition of FOXO3a restored proliferation and colony formation of Pdk1(-/-) melanoma cells. Our studies provide direct genetic evidence for the importance of PDK1, in part through FOXO3a-dependent pathway, in melanoma development and progression.

Desmoplastic melanoma: a 12-year experience with sentinel lymph node biopsy.

AIMS: Given the paucity of data regarding nodal involvement in desmoplastic melanoma (DM), we decided to review the incidence of nodal metastasis in our patients with DM to better define guidelines regarding the performance of sentinel lymph node biopsy (SLNB) in this specific melanoma subtype. METHODS: Using a prospectively maintained database, we reviewed all patients who underwent treatment for melanoma at the Yale Melanoma Unit in a twelve-year period (1998-2010), during which 3531 cases were treated. We identified 24 patients (0.7%) diagnosed with DM. These patients' records were studied for clinical and histologic parameters and clinical outcomes. RESULTS: Twenty-two patients from the DM group had SLNB, of which four (18%) were diagnosed with micro-metastasis. These four patients were all treated with completion lymphadenectomy and none had additional positive nodes in the remainder of the nodes. Patients were followed after surgery for a median of 25 months (range 2-60 months). Two patients (9%) developed local recurrence, two (9%) in-transit recurrence, and six (27%) showed distant metastases (three patients were pure DM and three patients showed mixed morphology). Patients with mixed DM had a higher rate of nodal metastasis (25%) vs those with pure DM (14%). CONCLUSIONS: Other authors have reported that patients diagnosed with pure DM were less likely to have a positive SLN (0-2%) than those patients with the mixed DM subtype (12-16%). Our findings of higher incidence rates of regional lymph node metastases in both the pure and mixed DM subtypes (14% and 25%) compel us to continue to still recommend that SLNB be considered in patients with both subcategories, pure and mixed DM. LEVEL OF EVIDENCE: Level IV.

A Variant in a MicroRNA complementary site in the 3' UTR of the KIT oncogene increases risk of acral melanoma.

MicroRNAs (miRNAs) are small ∼22nt single stranded RNAs that negatively regulate protein expression by binding to partially complementary sequences in the 3' untranslated region (3' UTRs) of target gene messenger RNAs (mRNA). Recently, mutations have been identified in both miRNAs and target genes that disrupt regulatory relationships, contribute to oncogenesis and serve as biomarkers for cancer risk. KIT, an established oncogene with a multifaceted role in melanogenesis and melanoma pathogenesis, has recently been shown to be upregulated in some melanomas, and is also a target of the miRNA miR-221. Here, we describe a genetic variant in the 3' UTR of the KIT oncogene that correlates with a greater than fourfold increased risk of acral melanoma. This KIT variant results in a mismatch in the seed region of a miR-221 complementary site and reporter data suggests that this mismatch can result in increased expression of the KIT oncogene. Consistent with the hypothesis that this is a functional variant, KIT mRNA and protein levels are both increased in the majority of samples harboring the KIT variant. This work identifies a novel genetic marker for increased heritable risk of melanoma.

Reactive angioendotheliomatosis. Case report and review of the literature.

Angioendotheliomatosis is an uncommon disease characterized histologically by proliferation of cells within vascular lumina with secondary intravascular thrombi resulting in obliteration of the involved vessels. While angioendotheliomatosis was initially thought to be a single disease entity, recent studies show that the disease may be divided into benign (reactive) and malignant variants, with the malignant variant representing intravascular malignant lymphoma. The reactive variant is rare, with only 16 cases reported in the literature, and is characterized histologically by proliferating endothelial cells within vessel lumina. In this report we present a case of reactive angioendotheliomatosis and review the literature on this rare entity.

Partial unilateral lentiginosis with ocular involvement.

Partial unilateral lentiginosis (PUL) is an unusual pigmentary disorder characterized by numerous lentigines grouped within an area of normal skin; the pigmented macules are often in a segmental distribution with a sharp demarcation at the midline. We report the first case of ocular involvement in a patient with this diagnosis. The patient, a 30-year-old Peruvian woman, had multiple brown macules on the left upper face in primarily a V1 and V2 distribution with a sharp demarcation at the midline of the forehead. The lesions first appeared near the hairline when she was 5 years of age, and then began to extend onto the face. She also had a discrete area of brown pigmentation on the left lateral bulbar conjunctiva. Because the patient had been previously diagnosed by several dermatologists as having either a speckled lentiginous nevus or a nevus of Ota, we draw attention to the entity PUL and the possibility of ocular involvement.

LN-2 (CD74). A marker to distinguish atypical fibroxanthoma from malignant fibrous histiocytoma.

BACKGROUND: In this study, the authors examined the expression of LN-2, an antigen expressed by B cells, macrophages, and Reed-Sternberg cells, in a variety of spindle cell lesions of the skin to determine whether LN-2 immunoreactivity can be used to differentiate among these tumors. For comparison, they examined CD34 antigen expression in these lesions, which has been shown to be a useful marker in differentiating dermatofibrosarcoma protuberans from dermatofibroma. METHODS: Immunocytochemistry with anti-LN-2 and anti-CD34 monoclonal antibodies on formalin fixed, paraffin embedded material was performed on 102 spindle cell lesions, including dermatofibroma, dermatofibrosarcoma protuberans, atypical fibroxanthoma, malignant fibrous histiocytoma, leiomyoma, and neurofibroma. RESULTS: LN-2 immunoreactivity did not distinguish between dermatofibroma and dermatofibrosarcoma protuberans, both of which showed weak immunoreactivity. In marked contrast, 90% of cases of malignant fibrous histiocytoma showed strong staining for LN-2, whereas the vast majority (90%) of cases of atypical fibroxanthoma were negative or stained only weakly with anti-LN-2 antibodies. Of the two cases of atypical fibroxanthoma that stained strongly for LN-2, both lesions were > 2 cm in size and extended deep into the subcutaneous fat. CONCLUSIONS: Differential expression of the LN-2 antigen by atypical fibroxanthoma and malignant fibrous histiocytoma distinguishes these two lesions and suggests that acquisition of LN-2 positivity may be a marker of tumor progression.

A figurate papulosquamous variant of inflammatory vitiligo.

The classic description of inflammatory vitiligo is an erythematous rim at the periphery of a patch of hypopigmented or depigmented skin. The histological correlate is a superficial perivascular infiltrate of mononuclear cells. However, we observed a 61-year-old patient with inflammatory vitiligo who had thin solid pink scaly plaques as well as serpiginous lesions with fine scale. Histologically, a lichenoid infiltrate was seen as was a thickened stratum corneum with parakeratosis. In a review of the literature, scattered case reports of similar findings were identified, either in the Japanese and French literature or from over 25 years ago. The clinical and histological spectrum of inflammatory vitiligo should be expanded to include solid and annular papulosquamous plaques as well as lichenoid infiltrates with exocytosis.

The development of lentigines within segmental achromic nevi.

The classic definition of a nevus depigmentosus is a stable congenital leukoderma that may be localized, segmental, or less often, systematized. Herein we report 2 patients whose achromic nevi underwent an unusual change--the development of multiple lentigines. The lentigines ranged in size from 3 to 5 mm and the majority had an irregular outline. Although their color was darker than that of the normal surrounding skin, the most striking clinical finding was their limited distribution. The lentigines were present only within the confines of the nevus depigmentosus. They first appeared at age 3 years in 1 child and at age 1 year in the second. No new pigmented macules were noted in the older child after age 10 years and, by that time, greater than 90% of the nevus depigmentosus was "repigmented." One possible explanation would be the reversion of a mutation in 1 of the genes involved in pigmentation.

Unusual halo nevi--darkening rather than lightening of the central nevus.

Although the classic halo nevus is a brown nevus with a surrounding rim of depigmentation, i.e. a stage I halo nevus, these nevi can have several clinical stages. The central nevus may lose its pigmentation and appear pink with a surrounding halo (stage II), the central papule may disappear leading to a circular area of depigmentation (stage III) or the depigmented area may repigment (stage IV), leaving no trace of its prior existence. Herein we describe an unusual phenomenon--darkening of the central nevus rather than lightening--following the appearance of the halo phenomenon. An 18-year-old boy who had multiple atypical nevi developed multiple halo nevi beginning at the age of 12 years. Following the appearance of the peripheral halos, 2 of his nevi that were originally solid medium brown in color darkened and the hyperpigmentation had a reticulated pattern with perifollicular sparing. One possible explanation is a postinflammatory hyperpigmentation induced by the infiltrating lymphocytes.

Morphea limited to the superficial reticular dermis: an underrecognized histologic phenomenon.

Morphea (localized scleroderma) is a disease of unknown etiology, presenting as circumscribed areas of indurated skin. Histologically, most cases of morphea feature thickened collagen bundles in the deep reticular dermis, sometimes also extending into the superficial dermis or into the subcutis. We present six cases of morphea in which typical histologic features were restricted to the superficial dermis and contrast these with 27 additional biopsies of conventional morphea seen during the same time period. Sections were stained for elastic fibers, and dermal dendritic cells were labeled with antibodies to CD34 and Factor XIIIa. All six cases showed thickened collagen bundles restricted to the superficial dermis, sparing the deep dermis and without associated evidence of lichen sclerosus et atrophicus (LSA). Dermal elastic fibers were not appreciably decreased in number. There was loss of CD34-positive dermal spindle cells in each of our six superficial examples of morphea, which was restricted to the area of altered collagen in four of the six cases. This report highlights the distinctly uncommon phenomenon of morphea presenting solely as alteration of the superficial reticular dermis, without features of LSA. The selective loss of CD34-labeled spindle cells may provide information regarding the role of these putative immune accessory cells in morphea. Recognition of this manifestation of morphea may be helpful diagnostically.