Malignant tumors of melanocytes : Part 3. Deba P Sarma, MD., Omaha

Transcription

1 Malignant tumors of melanocytes : Part 3 Deba P Sarma, MD., Omaha

2 Let s go over one case of melanoma using the following worksheet. Of the various essential information that needs to be included in the diagnosis (diagnosis with subtype, tumor thickness in mm, presence or absence of ulceration, mitotic rate, level of invasion, margin status and pathologic stage), most critical items are the diagnosis of melanoma, tumor thickness and presence or absence of ulceration. Diagnosis: SKIN, SITE,BIOPSY / EXCISION: - Diagnosis with subtype -Tumor thickness (Breslow depth): mm -Ulceration: Absent / Present -Mitotic rate: 0 or 1 or more/ mm 2 -Level of invasion (Clark level): -Margin status: Negative / Positive -Pathologic stage: ADDITIONAL OPTIONAL INFORMATION: Microsatellitosis: Absent/ Present Dense tumor-infiltrating lymphocytes: Absent / present Histologic subtype: Lentigo Maligna / Superficial spreading / Nodular / Acral lentiginous / Desmoplastic Clark s Level: I (in situ), II (papillary dermis), III (up to papillary-reticular interface), IV (reticular dermis), V (subcutis) Pathologic Stage: (ptnm): ptx Primary tumor cannot be assessed PTO No evidence of primary tumor ptis Melanoma in-situ pt1a Melanoma 1 mm or less thick, no ulceration and mitosis 0 per mm squared pt1b Melanoma 1 mm or less thick, with ulceration or mitosis 1 or more per mm squared pt2a Melanoma mm thick, no ulceration pt2b Melanoma mm thick, with ulceration pt3a Melanoma mm thick, no ulceration pt3b Melanoma mm thick, with ulceration pt4a Melanoma > 4 mm thick, no ulceration pt4b Melanoma > 4 mm thick, with ulceration Regional Lymph Nodes (pn) Distant Metastasis (pm)

3 Case 1. F 67, dorsal left hand, biopsy Let s scan the slide in 4X No ulceration What do we see? - Epidermis is slightly raised, intact, hyperkeratotic. NO ULCERATION. - A tumor starting from the basal layer growing laterally as well as downwards in the papillary dermis. So the level of invasion is Level II (Papillary dermis). - Both lateral margins (lateral to thin red arrows) and the deep MARGINS ARE NEGATIVE for tumor. - In higher magnification, you see the highly pleomorphic, pigmented neoplastic melanocytes from the basal nests extending in the papillary dermis are growing into tumor clones. The overlying epidermis does not show neoplastic melanocytes with pale cytoplasm (Pagetoid cells). - Your diagnosis is: Melanoma, lentigo maligna type or simply Lentigo maligna melanoma.

4 Now, let s look at 10X Tumor thickness: 0.30 mm You have to measure the tumor thickness at 10X using a micro-oculometer. You scan the deep part of the tumor and find the deepest clone (a clump of at least 4-5 neoplastic cells) and measure from the deepest tumor margin to the top of the granular layer of the epidermis. Micro-oculometer has a scale reading 1 mm divided in 100 lines it is a direct read-out. You may measure three different areas and record the maximum thickness (remember, it is not the average of 3 readings! It is the deepest measurement).

5 Now, we have to count mitotic rate of this melanoma. We scan the tumor islands only in the dermis (not at the basal epidermis) at 40X, count the number of mitosis in 4 active areas (hot zones), and record them as : Number of mitosis per mm 2 Mitotic figure After scanning 4 different areas in the dermis I counted 2 mitosis per mm squared. This will be recorded as: Mitotic rate: > 1 per mm2

6 Now, two optional information Microsatellitosis is defined as small tumor islands, 0.05 mm or larger in size in the reticular dermis or subcutis separated from the main tumor by at least 0.3 mm. We record our case as : Microsatellitosis: Absent Dense tumor-infiltrating lymphocytes: Present Lymphocytes Melanoma

7 Now, let s look at the worksheet, and figure out the Pathologic stage for this case Pathologic Stage: (ptnm): ptx Primary tumor cannot be assessed PTO No evidence of primary tumor ptis Melanoma in-situ pt1a Melanoma 1 mm or less thick, no ulceration and mitosis 0 per mm squared pt1b Melanoma 1 mm or less thick, with ulceration or mitosis 1 or more per mm squared pt2a Melanoma mm thick, no ulceration pt2b Melanoma mm thick, with ulceration pt3a Melanoma mm thick, no ulceration pt3b Melanoma mm thick, with ulceration pt4a Melanoma > 4 mm thick, no ulceration pt4b Melanoma > 4 mm thick, with ulceration Regional Lymph Nodes (pn) Distant Metastasis (pm) Our findings in this case are: Primary Tumor (pt): 0.30 mm thick, no ulceration, mitotic rate >1 per mm2 Regional Lymph Nodes (pn): X (unknown) Distant Metastasis: X (unknown) Pathologic stage is recorded as: pt1b, pnx, pmx

8 Now, let s write the final diagnosis Diagnosis: SKIN, dorsal left hand,biopsy : -Melanoma, lentigo maligna type -Tumor thickness (Breslow depth): 0.30 mm -Ulceration: Absent -Mitotic rate: > 1/ mm 2 -Level of invasion (Clark level): II -Margin status: Negative -Pathologic stage: pt1b, pnx, pmx Additional information: Microsatellitosis: Absent Dense tumor-infiltrating lymphocytes: Present ds

9 Let s go over a few important points: Diagnosis of melanoma is usually done at 4X or 10X magnification, mostly from the alteration of growth pattern of melanocytes. Thickness of melanoma is measured at 10X magnification using a micro-oculometer. Thickness of the tumor is measured from deepest part of the tumor to the top of granular layer of the epidermis. In case the overlying epidermis is ulcerated, thickness is measured from deepest part of the tumor to the base of ulcer. Mitotis is counted in the invasive part of the tumor (not at basal area) in the active part of the tumor at 40X magnification. Suggestion: You have to sit with your staff pathologist or dermatopathologist to practice reading melanoma using a binocular or a multiheaded microscope. You have to read several cases before you feel confident. After a while, it will be your second nature. Deba P Sarma, MD., Omaha