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| ==Melanoma== | | ==Melanoma== |
| | {{Main|Malignant melanoma}} |
| ===General=== | | ===General=== |
| *[[AKA]] ''Malignant melanoma''.
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| *Main DDx: [[melanocytic lesions]] - especially if pigmented.
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| *Known as the great mimicker in pathology; it may look like many things. | | *Known as the great mimicker in pathology; it may look like many things. |
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| ====Clinical====
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| *''ABCD'' = asymmetric, borders (irregular), colour (black), diameter (large).
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| ===Microscopic=== | | ===Microscopic=== |
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| **Marked nuclear pleomorphism - variation in cell size, shape & staining (like in ''serous carcinoma'' of the ovary). | | **Marked nuclear pleomorphism - variation in cell size, shape & staining (like in ''serous carcinoma'' of the ovary). |
| **[[Nuclear pseudoinclusions]] (like in ''papillary thyroid carcinoma''). | | **[[Nuclear pseudoinclusions]] (like in ''papillary thyroid carcinoma''). |
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| Notes:
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| *Can look almost like anything.
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| **Like it is said that [[sarcoidosis]] is in every internal medicine DDx... melanoma is every pathologic DDx.
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| *Melanomas with:
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| **An epitheloid cell morphology may mimic adenocarcinoma.
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| **A spindle cell morphology may mimic spindle cell carcinoma (squamous cell carcinoma) or a sarcoma.
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| ===[[Electron microscopy]]===
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| *Melanosomes.
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| Image(s):
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| *[http://www.nature.com/nrm/journal/v8/n10/fig_tab/nrm2258_F1.html Melanosomes (nature.com)].
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| ===Stains===
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| *''Fontana-Masson stain'', stains melanin.<ref>URL: [http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm]. Accessed on: 5 May 2010.</ref>
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| **May be useful to differentiate melanin from other brown stuff (e.g. lipofuscin, hemosiderin).
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| ===[[IHC]]===
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| Standard panel:
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| *S-100 +ve.
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| *HMB-45 +ve.
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| *Melan A (MART-1) +ve.
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| Others:
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| *SOX10 +ve -- useful for diff. from excision scar.<ref name=pmid20653825>{{cite journal |author=Ramos-Herberth FI, Karamchandani J, Kim J, Dadras SS |title=SOX10 immunostaining distinguishes desmoplastic melanoma from excision scar |journal=J. Cutan. Pathol. |volume=37 |issue=9 |pages=944–52 |year=2010 |month=September |pmid=20653825 |doi=10.1111/j.1600-0560.2010.01568.x |url=}}</ref>
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| **SOX-10 = pan-schwannian and melanocytic marker.
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| Notes:
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| *The standard panel above (S-100, HMB-45, MART-1) is also positive in other lesions, e.g. ''cellular blue nevus''.
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| ==Dermatofibrosarcoma protuberans== | | ==Dermatofibrosarcoma protuberans== |