Amelanotic corneally displaced malignant conjunctival melanoma: a case report evaluated with impression cytology.

Here we describe the case of a 65-year-old Caucasian female who presented with an amelanotic malignant conjunctival melanoma and highlight the clinical and pathological features of this rare entity that displayed exclusive corneal invasive growth without evidence of conjunctival tumors other than primary acquired melanosis. Impression cytology aided in the initial diagnosis. The patient underwent surgical treatment. Histopathology and immunohistochemistry revealed an invasive amelanotic melanoma limited to the cornea and exhibiting S-100, Melan A, and HMB-45 positivity. The absence of pigmentation delayed early clinical detection and treatment. Awareness of this nonpigmented melanoma is important for early recognition and appropriate management.

Amelanotic corneally displaced malignant conjunctival melanoma: a case report evaluated with impression cytology / Melanoma amelanótico conjuntival maligno deslocado sobre a córnea com citologia de impressão: relato de caso

Here we describe the case of a 65-year-old Caucasian female who presented with an amelanotic malignant conjunctival melanoma and highlight the clinical and pathological features of this rare entity that displayed exclusive corneal invasive growth without evidence of conjunctival tumors other than primary acquired melanosis. Impression cytology aided in the initial diagnosis. The patient underwent surgical treatment. Histopathology and immunohistochemistry revealed an invasive amelanotic melanoma limited to the cornea and exhibiting S-100, Melan A, and HMB-45 positivity. The absence of pigmentation delayed early clinical detection and treatment. Awareness of this nonpigmented melanoma is important for early recognition and appropriate management.

Os autores descrevem o caso de uma mulher branca de 65 anos que apresentava um melanoma amelanótico maligno conjuntival e destacam as características clínicas e patológicas desta entidade rara com crescimento invasivo exclusivo na córnea sem evidência de tumores na conjuntiva além de melanose adquirida primária sem pigmento. A citologia de impressão auxiliou no diagnóstico inicial. A paciente foi submetida a tratamento cirúrgico. A histopatologia e a imuno-histoquímica revelaram um melanoma amelanótico invasivo limitado sobre a córnea exibindo positividade para proteína S-100, Melan A e HMB-45. A ausência de pigmentação retardou sua identificação clínica e seu tratamento precoce. O conhecimento deste melanoma não pigmentado é importante para o reconhecimento precoce e a conduta apropriada.

Large neglected ulcerated melanoma mimicking extramedullary plasmacytoma.

Amelanotic melanoma, a renowned impersonator, has taken on a new persona. A 63-year-old woman was seen in the emergency room with a chief complaint of back pain after a fall and was discovered to have a 15-cm fungating mottled gray mass independent of bone on the right elbow. Initial workup discovered lytic calvarial lesions, anemia (Hb 7; Hct 20%), and circulating plasma cells consistent with plasma cell myeloma. Biopsy of the elbow mass displayed sheets of plasmacytoid cells, some reactive for CD138. Flow cytometry revealed a substantial portion of the plasma cells in the tumor that were kappa restricted consistent with cutaneous plasmacytoma. The elbow mass was initially signed out as extramedullary involvement by her myeloma. Reevaluation of the mass after the patient experienced an explosive growth of multinodular jet black malignant melanoma on ipsilateral breast revealed MART-1 and S-100 reactivity of the majority of the cells. In retrospect, the elbow mass was a neglected primary amelanotic malignant melanoma with neoplastic plasma cells participating in its chronic inflammatory infiltrate.

Re-evaluation of melanin bleaching using warm diluted hydrogen peroxide for histopathological analysis.

Excessive amounts of melanin pigments may hamper histopathological assessments of melanocytic lesions by obscuring cellular morphology and hindering antibody-antigen interactions. To determine the optimal melanin-bleaching conditions for histopathological examination, heavily pigmented melanomas were treated with warm hydrogen peroxide (H2O2) diluted with various diluents (1% disodium hydrogen phosphate 12H2O (Na2 HPO4); phosphate buffer 0.05 M, pH 7.4 (PB); and PBS 0.05 M, pH 7.4) at varying temperatures (50°C, 55°C, and 60°C) and for varying incubation times (0.5, 1, 2, and 3 h). The effect of the sequential order of antigen retrieval and bleaching on preserving tissue morphology was then evaluated. Additionally, the effect of melanin bleaching using warm diluted H2O2 on the antigenicity of melanoma-related markers (HMB-45, MART-1, and S-100) and other markers used for histopathology was examined in amelanotic melanomas and tonsil tissue. Optimal and complete bleaching was achieved using warm 3% H2O2 in PB treatment at 55°C for 2 h following antigen retrieval with microwaving or digestion with trypsin. Under these conditions, the tissue morphology and antigenicity of various immunohistochemical markers were also well preserved. Bleaching with warm 3% H2O2 PB is a fast and efficient method of bleaching melanin pigments and performing immunohistochemical examination in heavily melanin-pigmented lesions.

Amelanotic vulvar melanoma with intratumor histological heterogeneity.

Amelanotic vulvar melanoma is a rare type of malignant melanoma. This paper describes a case of an asymptomatic ulcerated nodule 20 mm in size. The tumor cells from the nodular lesion showed positive staining immunohistochemically for Melan-A, but negative staining with HMB-45. The cells showed negative reactivity to S-100 except in one region. The melanoma cells in the epidermis were detected in one of the specimens from the excised tumor nodule. The cells in the epidermis showed positive staining for Melan-A and S-100 and partial staining with HMB-45. The tumor was diagnosed as malignant melanoma of the vulva and immunohistochemically shown to have intratumor histological heterogeneity. This case suggests the importance of viewing non-pigmented nodules on the vulva of elderly females as potentially malignant melanoma, and that a combination of immunohistochemical stains may be useful for recognizing the stage of the melanosomes in the melanoma cells.

Primary amelanotic malignant melanoma of the parotid gland: a case report.

Amelanotic malignant melanoma in the oral region is extremely rare and has not previously been reported in the parotid gland. This present case report describes an amelanotic malignant melanoma in the parotid gland, with no other primary lesion detectable. The medical history, pathology and immunohistochemical analysis of the case are described and the relevant literature is reviewed in order to help in the recognition of this uncommon tumour. Amelanotic malignant melanoma is a melanoma subtype with little or no pigmentation and, because of this lack of pigmentation and its wide-ranging clinical appearance, it often defies clinical diagnosis. A high level of vigilance is, therefore, necessary in diagnosing such a tumour in the parotid gland. Where it is suspected, positive expression of S-100 protein and human melanoma black 45(HMB45) using immunohistochemical analysis can be considered reliable methods of confirming diagnosis.

Small cell malignant melanoma: an unusual morphologic variant.

Small cell melanoma is a recognized rare variant of malignant melanoma. We report a case of a brown, ulcerated papule on the left third finger of an 80-year-old woman. Microscopic examination revealed the presence within the epidermis of diffuse sheets of monomorphic small to medium-sized cells. The nuclei were round or oval, and hyperchromatic with inconspicuous nucleoli. Melanin pigment was either absent or minimal. This case report draws attention to the difficulties encountered in the histological diagnosis of this rare variant of malignant melanoma.

Bilateral diffuse melanocytic proliferation associated with ovarian carcinoma and metastatic malignant amelanotic melanoma.

PURPOSE: To report a case of metastatic malignant amelanotic melanoma to the skin from a patient diagnosed with bilateral diffuse uveal melanocytic proliferation (BDUMP). This dermatological finding is a unique phenomenon associated with BDUMP. DESIGN: Retrospective case report. METHODS: We studied the case of a 66-year-old Caucasian woman with gradual onset of blurred vision in her right eye followed by her left eye. She had previously been diagnosed with ovarian carcinoma, and findings of funduscopic examinations were consistent with BDUMP. Metastatic examination revealed no evidence of liver involvement. Clinical and histopathological examinations of both enucleated eyes were consistent with BDUMP. RESULTS: The hematoxylin and eosin, S-100, and HMB-45 stains were consistent with metastatic malignant amelanotic melanoma to the skin. CONCLUSIONS: Although believed to have a low potential for metastasis, patients should be monitored and evaluated regularly to detect any new lesions not associated with their primary inciting carcinoma.

Cutaneous mass aspirate from a Golden Retriever: "glandular guile".

A 3-year-old, neutered, male Golden Retriever was presented for evaluation of a 10 X 9 X 5 mm, firm, red, raised, cutaneous mass located over the left cranial thorax and noted incidentally by the owner. On cytologic evaluation of a fine-needle aspirate of the mass, the interpretation was a malignant tumor with predominantly mesenchymal features. Differentials included liposarcoma, atypical amelanotic melanoma, anaplastic sarcoma, and anaplastic carcinoma. Following complete excision of the mass, a diagnosis of sebaceous adenocarcinoma was made based on histologic features, positive immunostaining for pancytokeratin, and negative staining for vimentin, Melan-A, and S-100. There was no evidence of metastasis on physical examination or thoracic radiographs, and the prognosis was good. The unique and previously unreported cytologic features of this small, sebaceous adenocarcinoma were the extreme pleomorphism, including marked anisocytosis, anisokaryosis, and multinuclearity, and the paucity of epithelial features.

Spontaneous uveal amelanotic melanoma in transgenic Tyr-RAS+ Ink4a/Arf-/- mice.

OBJECTIVE: To characterize a murine model of spontaneous amelanotic melanoma arising in the uvea of transgenic mice bearing a targeted deletion of the Ink4a/Arf tumor suppressor locus (exons 2 and 3) and expressing human H-ras controlled by the human tyrosinase promoter. METHODS: Ocular lesions developed in 20 (15.7%) of 127 male albino Tyr-RAS+ Ink4a/Arf-/- transgenic FVB/N mice within 6 months, and were evaluated histologically and ultrastructurally. RESULTS: Uveal melanomas were locally invasive but confined to the eye, with no evidence of metastasis. Tumor cells exhibited epithelioid and spindle-shaped morphological features and closely resembled the human counterpart. Melan-A, S100 and neuron-specific enolase expression were detected immunohistochemically. Melanosomal structures were detected using electron microscopy. The retinal pigment epithelium was intact above small melanomas, and electron microscopy of the tumors failed to show the presence of basement membrane formation or desmosomes. CONCLUSION: Spontaneous uveal malignant melanomas occurring in male Tyr-RAS+ Ink4a/Arf-/- transgenic mice arise within the choroid or ciliary body and share histopathological features characteristic of human uveal melanoma. CLINICAL RELEVANCE: Uveal melanoma research has benefited from xenograft models, but engineered mouse models of spontaneous uveal amelanotic melanoma will undoubtedly further our understanding of the genetic underpinning for this disease.

Cavitary choroidal melanoma.

CASE REPORT: We report an unusual case of cavitary choroidal melanoma. The results of ultrasonography, magnetic resonance imaging, computed tomography, and immunohistochemical studies are presented for a 38-year-old woman who developed an amelanotic tumor in the posterior choroid. B-scan ultrasonography disclosed intratumoral cavitations. Systemic and extraocular extension studies were negative. Enucleation was performed and histopathologic examination showed a choroidal melanoma of spindle cell type, with intratumoral cavitations lined by flattened tumor cells. COMMENTS: The majority of previous reports of intraocular cavitary tumors describe cavitary ciliary body tumors. Uveal melanoma should be included in the differential diagnosis of choroidal cavitary lesions. As far as we know, this is the second documented clinicopathologic correlation of a cavitary choroidal melanoma.

Platinum complex cytotoxicity tested by the electrical resistance breakdown assay.

The electrical resistance breakdown assay provides a novel approach for the quantification of cytotoxic activity of platinum based anticancer drugs. It is a functional assay system for cancer cell invasion that detects nanoscale alterations of an epithelial test barrier prior to microscopic morphometric changes. We measured changes in transepithelial electrical resistance (TEER) of a tight epithelial MDCK-C7 monolayer in response to highly invasive amelanotic melanoma cells (A7-clone) in combination with different platinum complexes (cis-, oxali- and carboplatin). The efficiency of the electrical resistance breakdown assay was compared a standard method for measurement of cytostatic activity, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The MTT-assay utilizes mitochondrial enzymatic activity to draw conclusions from a functional cell metabolism to the number of living cells in a sample. When human melanoma cells were seeded on top of an electrically tight MDCK-C7 monolayer, electrical leakage occurred within 48 h of co-culture. Electrical resistance breakdown was effectively prevented by cisplatin and its analogs (no significant difference between 100 microM cisplatin and corresponding controls with non-invasive cells). The results of the electrical resistance breakdown and MTT-assay were linearly dependent. Significance of both tests was equivalent, but the electrical resistance breakdown assay gave additional functional information. Compared to oxali- and carboplatin, cisplatin was more effective in preventing TEER-breakdown than reducing the number of tumor cells, giving rise to the assumption that cisplatin can reduce tumor cell number as well as invasiveness. In conclusion the electrical resistance breakdown assay provides a sensitive, continuous and cell-based assay system for the quantification of cancer cell invasiveness and evaluation of chemotherapeutics under physiological conditions.

Subungual amelanotic melanoma.

We describe a 76-year-old white male with subungual amelanotic melanoma. The lack of pigmentation of the lesion may cause misdiagnosis and aggravate its poor prognosis.

A case of amelanotic spindle-cell melanoma presenting as metastases to breast and axillary lymph node: diagnosis by FNA cytology.

Metastatic neoplasms to the breast are relatively rare. Spindle-cell lesions of the breast are also uncommon. Here we present a case of fine-needle aspiration (FNA) of an amelanotic, spindle-cell melanoma metastatic to the breast and axillary lymph node. The patient was a 47-yr-old female who presented with a right breast mass, left axillary adenopathy, and a pigmented skin lesion on the back. FNA of the right breast and left axilla showed malignant, nonpigmented spindle cells that were weakly positive for HMB-45 on immunocytochemistry. The skin biopsy showed a pigmented malignant melanoma with epithelioid features, and also weak positivity for HMB-45. Although malignant melanoma is one of the more common tumors to metastasize to the breast, this is the first known case that showed exclusive spindle-cell morphology. History and physical examination were crucial in making the correct FNA diagnosis. The cytologic differential diagnosis of spindle-cell tumors of breast and the discordant morphology between the primary and metastatic melanotic lesions observed in this case are discussed.