Clear Cell Differentiation in Choroidal Melanoma

Endoscopic enucleation and clinicopathologic correlation of a small choroidal melanoma hiding massive extrascleral extension

“…With an estimated prevalence of just 0.1%, this finding is rarely associated with choroidal melanoma. 14 Electron microscopy suggests these clear cells might represent altered melanocytes undergoing metamorphosis, with degeneration of intracellular melanosomes. 15 In our case, staining of the clear cell component with Melan A confirms this possibility.…”

Endoscopic enucleation and clinicopathologic correlation of a small choroidal melanoma hiding massive extrascleral extension

“…With an estimated prevalence of just 0.1%, this finding is rarely associated with choroidal melanoma. 14 Electron microscopy suggests these clear cells might represent altered melanocytes undergoing metamorphosis, with degeneration of intracellular melanosomes. 15 In our case, staining of the clear cell component with Melan A confirms this possibility.…”

Choroidal Melanoma Mimicker: A Case of Metastatic Clear-Cell Renal Cell Carcinoma

“…Immunohistochemistry aids differentiation of these entities from clear-cell metastases. Clear-cell uveal melanomas demonstrate positive staining with the melanocytic markers S-100 and HMB-45 [9]. The tumor in this case was negative for melanocytic markers, which included S-100, Melan-A, tyrosinase, and HMB-45, making it unlikely to represent one of these uveal melanoma variants.…”

“…Balloon cells may be observed in choroidal melanoma post radiation and represent degraded melanosomes [8]. Clear-cell melanoma comprises a distinct subtype of uveal melanoma identified in 2 of the 1,493 eyes enucleated and reviewed in the Collaborative Ocular Melanoma Study [9]. Immunohistochemistry aids differentiation of these entities from clear-cell metastases.…”

Genetics and RNA Regulation of Uveal Melanoma

“…Because this "old" classification lacked reproducibility among pathologists and prognostic relevance, it was simplified over time, and the American Joint Committee on Cancer (AJCC) now recognizes three histologic subtypes of UM [46,47]: (i) spindle cell type (typically composed of both spindle A and spindle B cells and exhibiting spindle cell morphology in 90% of tumor); (ii) epithelioid cell type (exhibiting epithelioid cell morphology in 90% of tumor); and (iii) mixed cell type. Further unusual morphological variants of UM have been described: (a) diffuse UM, defined as tumors involving at least one-quarter of the uvea [48]; (b) clear cell UM, characterized by diffuse clear cell morphology caused by glycogen dissolution after fixation [49]; and (c) balloon cell UM, showing large tumor cells with abundant lipid-rich cytoplasm [50,51]. UM cells are commonly stained with melanocytic differentiation markers such as S-100, human melanoma black 45 (HMB45), melan-A/melanoma antigen recognized by T cells 1 (MART-1), melanocyte-inducing transcription factor (MITF) and sex-determining region Y-box 10 (SOX10) [52][53][54][55].…”

Endoscopic enucleation and clinicopathologic correlation of a small choroidal melanoma hiding massive extrascleral extension

“…With an estimated prevalence of just 0.1%, this finding is rarely associated with choroidal melanoma. 14 Electron microscopy suggests these clear cells might represent altered melanocytes undergoing metamorphosis, with degeneration of intracellular melanosomes. 15 In our case, staining of the clear cell component with Melan A confirms this possibility.…”

Choroidal Melanoma Mimicker: A Case of Metastatic Clear-Cell Renal Cell Carcinoma

“…Immunohistochemistry aids differentiation of these entities from clear-cell metastases. Clear-cell uveal melanomas demonstrate positive staining with the melanocytic markers S-100 and HMB-45 [9]. The tumor in this case was negative for melanocytic markers, which included S-100, Melan-A, tyrosinase, and HMB-45, making it unlikely to represent one of these uveal melanoma variants.…”

“…Balloon cells may be observed in choroidal melanoma post radiation and represent degraded melanosomes [8]. Clear-cell melanoma comprises a distinct subtype of uveal melanoma identified in 2 of the 1,493 eyes enucleated and reviewed in the Collaborative Ocular Melanoma Study [9]. Immunohistochemistry aids differentiation of these entities from clear-cell metastases.…”

Genetics and RNA Regulation of Uveal Melanoma

“…Because this "old" classification lacked reproducibility among pathologists and prognostic relevance, it was simplified over time, and the American Joint Committee on Cancer (AJCC) now recognizes three histologic subtypes of UM [46,47]: (i) spindle cell type (typically composed of both spindle A and spindle B cells and exhibiting spindle cell morphology in 90% of tumor); (ii) epithelioid cell type (exhibiting epithelioid cell morphology in 90% of tumor); and (iii) mixed cell type. Further unusual morphological variants of UM have been described: (a) diffuse UM, defined as tumors involving at least one-quarter of the uvea [48]; (b) clear cell UM, characterized by diffuse clear cell morphology caused by glycogen dissolution after fixation [49]; and (c) balloon cell UM, showing large tumor cells with abundant lipid-rich cytoplasm [50,51]. UM cells are commonly stained with melanocytic differentiation markers such as S-100, human melanoma black 45 (HMB45), melan-A/melanoma antigen recognized by T cells 1 (MART-1), melanocyte-inducing transcription factor (MITF) and sex-determining region Y-box 10 (SOX10) [52][53][54][55].…”

Endoscopic enucleation and clinicopathologic correlation of a small choroidal melanoma hiding massive extrascleral extension

“…With an estimated prevalence of just 0.1%, this finding is rarely associated with choroidal melanoma. 14 Electron microscopy suggests these clear cells might represent altered melanocytes undergoing metamorphosis, with degeneration of intracellular melanosomes. 15 In our case, staining of the clear cell component with Melan A confirms this possibility.…”

Choroidal Melanoma Mimicker: A Case of Metastatic Clear-Cell Renal Cell Carcinoma

“…Immunohistochemistry aids differentiation of these entities from clear-cell metastases. Clear-cell uveal melanomas demonstrate positive staining with the melanocytic markers S-100 and HMB-45 [9]. The tumor in this case was negative for melanocytic markers, which included S-100, Melan-A, tyrosinase, and HMB-45, making it unlikely to represent one of these uveal melanoma variants.…”

“…Balloon cells may be observed in choroidal melanoma post radiation and represent degraded melanosomes [8]. Clear-cell melanoma comprises a distinct subtype of uveal melanoma identified in 2 of the 1,493 eyes enucleated and reviewed in the Collaborative Ocular Melanoma Study [9]. Immunohistochemistry aids differentiation of these entities from clear-cell metastases.…”

Genetics and RNA Regulation of Uveal Melanoma

“…Because this "old" classification lacked reproducibility among pathologists and prognostic relevance, it was simplified over time, and the American Joint Committee on Cancer (AJCC) now recognizes three histologic subtypes of UM [46,47]: (i) spindle cell type (typically composed of both spindle A and spindle B cells and exhibiting spindle cell morphology in 90% of tumor); (ii) epithelioid cell type (exhibiting epithelioid cell morphology in 90% of tumor); and (iii) mixed cell type. Further unusual morphological variants of UM have been described: (a) diffuse UM, defined as tumors involving at least one-quarter of the uvea [48]; (b) clear cell UM, characterized by diffuse clear cell morphology caused by glycogen dissolution after fixation [49]; and (c) balloon cell UM, showing large tumor cells with abundant lipid-rich cytoplasm [50,51]. UM cells are commonly stained with melanocytic differentiation markers such as S-100, human melanoma black 45 (HMB45), melan-A/melanoma antigen recognized by T cells 1 (MART-1), melanocyte-inducing transcription factor (MITF) and sex-determining region Y-box 10 (SOX10) [52][53][54][55].…”