case_images: PMC9941027_01
case_images: Cutaneous sebaceous carcinoma presenting as a red nodule on the chest of a 67-year-old male. Distant (A) and closer (B) views of the left side of the upper chest show an acquired lesion of three weeks duration presenting as a nontender, firm, 5 x 5-millimeter, red, smooth nodule (black arrow). The man has no personal or family history of cancer. The purple-inked oval designates the borders of the shave biopsy that was performed.
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case_images: FIG1
case_images: A 5 x 5-millimeter, red, smooth nodule was present on his upper chest, left of the midline (Figure 1); there were no palpable axillary lymph nodes.
case_images: Pathologic presentation of an extraocular cutaneous sebaceous carcinoma on the chest of a 67-year-old male. Distant (A) and closer (B, C, and D) views of the microscopic features of a sebaceous carcinoma show a basaloid nodule with prominent sebaceous differentiation in the dermis (within the black oval); the neoplasm appears to be extending from the squamous epithelium of a keratin-containing hair follicle located adjacent to the right side of the tumor. There are mature sebocytes (black arrows); however, approximately 90% of the tumor consists of crowded atypical-appearing basophilic-staining basaloid cells (red triangles) that have mitoses (hematoxylin and eosin stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_01_cureus-0015-00000033975-i02.jpg
case_images: FIG2
case_images: The basaloid cells made up approximately 90% of the tumor; the cells were crowded with multiple mitoses including atypical mitotic figures and apoptotic bodies (Figure 2).
case_images: Immunohistochemistry analysis of sebaceous carcinoma for MSH2 gene expression shows an absence of staining. Abbreviation: MSH2, MutS Homolog 2. Distant (A) and closer (B, C, and D) views of the tumor (within the black oval) show more than 90% loss of staining for MSH2. An absence of staining of the sebaceous carcinoma cells (black triangles) demonstrates a loss of expression of the MSH2 mismatch repair gene. Positive staining for MSH2 (black arrows) is present in the cells occupying the basal layers of the epidermis (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_01_cureus-0015-00000033975-i03.jpg
case_images: FIG3
case_images: There was a greater than 90% loss of MSH2 (Figure 3) and MSH6 (Figure 4) within the tumor.
case_images: Immunohistochemistry analysis demonstrates an absence of staining for MSH6 gene expression in a sebaceous carcinoma. Abbreviation: MSH6, MutS Homolog 6. Distant (A) and closer (B, C, and D) views demonstrate that there is a greater than 90% loss of staining for MSH6 in the sebaceous carcinoma (within the black oval). The basal layers of the epidermis and some of the cells at the periphery of the tumor show positive staining for MSH6 (black arrows). The absence of staining of the tumor cells (black triangles) shows a loss of expression of the MSH6 mismatch repair gene (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
case_images: cureus-0015-00000033975-i04.jpg
case_images: PMC9941027_01_cureus-0015-00000033975-i04.jpg
case_images: FIG4
case_images: There was a greater than 90% loss of MSH2 (Figure 3) and MSH6 (Figure 4) within the tumor.
case_images: Staining for MLH1 gene expression is prominent in immunohistochemistry analysis of the sebaceous carcinoma. Abbreviation: MLH1, MutL Homolog 1. Distant (A) and closer (B, C, and D) views of the tumor show strongly positive staining for MLH1 (within the black oval). The diffuse staining of the sebaceous carcinoma cells (red triangles) implies maintained expression of the MLH1 mismatch repair gene. Staining is also observed in the lower layers of the epidermis (black arrows) (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_01_cureus-0015-00000033975-i05.jpg
case_images: FIG5
case_images: However, there was retention of MLH1 (Figure 5) and PMS2 (Figure 6) within the dermal neoplasm.
case_images: The sebaceous carcinoma shows staining for PMS2 when immunohistochemistry analysis was performed. Abbreviation: PMS2, PMS1 Homolog 2, mismatch repair system component gene. Distant (A) and closer (B, C, and D) views show strongly positive staining for PMS2 in the sebaceous carcinoma (within the black oval); the lower layers of the epidermis also show staining (black arrows). The maintained expression of the PMS2 mismatch repair gene is implied by the diffuse staining of the tumor cells (red triangles) (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_01_cureus-0015-00000033975-i06.jpg
case_images: FIG6
case_images: However, there was retention of MLH1 (Figure 5) and PMS2 (Figure 6) within the dermal neoplasm.
case_images: PMC9941027_02
case_images: Sebaceous epithelioma presenting as a nodule on the lower left leg of a 74-year-old male. Abbreviation: JAK2, Janus kinase 2. Distant (A) and closer (B and C) views of a new 8 x 8-millimeter, flesh-colored nodule (black arrow) on the left pretibial leg of a male with myelodysplastic syndrome who was receiving an oral JAK2 inhibitor. His family history was significant for colon cancer, breast cancer, and acute myelogenous leukemia; he had no personal history of visceral malignancy. A shave biopsy was performed.
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case_images: FIG7
case_images: An 8 x 8-millimeter, partially crusted, flesh-colored nodule was present distal to his knee on the left anterior pretibial leg (Figure 7); there were no palpable inguinal lymph nodes.
case_images: Pathologic presentation of an extraocular cutaneous sebaceous carcinoma on the chest of a 74-year-old male. Distant (A) and closer (B, C, and D) views of the microscopic features of a sebaceous epithelioma show a tumor (within the black oval) that consists of numerous sebaceous lobules extending from the epidermis into the dermis; hemorrhagic crust overlies the epidermis. The tumor consists predominantly of basophilic germinative cells (red triangles) admixed with more mature sebaceous cells (black arrows). Atypical mitotic figures, within some of the tumor cells, are also observed (red arrows) (hematoxylin and eosin stain: A, x4; B, x10; C, x20; D, x40).
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case_images: FIG8
case_images: In the planes of the sections examined, the lateral margins and the base of the specimen were not involved by the tumor (Figure 8).
case_images: Immunohistochemistry analysis of sebaceous epithelioma for PMS2 expression shows an absence of staining. Abbreviation: PMS2, PMS1 Homolog 2, mismatch repair system component gene. Distant (A) and closer (B, C, and D) views of the tumor (within the black oval) show a complete loss of staining for PMS2. An absence of staining of the sebaceous epithelioma cells (black triangles) demonstrates a loss of expression of the PMS2 mismatch repair gene. Positive staining for PMS2 (black arrows) is present in the normal epidermis adjacent to the tumor (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_02_cureus-0015-00000033975-i09.jpg
case_images: FIG9
case_images: There was a complete loss of PMS2 staining (Figure 9).
case_images: Staining for MLH1 gene expression is prominent in the sebaceous epithelioma when immunohistochemistry analysis was performed. Abbreviation: MLH1, MutL Homolog 1. Distant (A) and closer (B, C, and D) views of the tumor show strongly positive staining for MLH1 (within the black oval). The diffuse staining of the lower portion of the sebaceous epithelioma cells (red triangles) implies maintained expression of the MLH1 mismatch repair gene. Staining for MLH1 is also observed in the normal adjacent epidermis (black arrows) (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_02_cureus-0015-00000033975-i10.jpg
case_images: FIG10
case_images: There was no loss of staining with MLH1 (Figure 10), MSH2 (Figure 11), and MSH6 (Figure 12).
case_images: Immunohistochemistry analysis of sebaceous epithelioma for MSH2 gene expression shows staining. Abbreviation: MSH2, MutS Homolog 2. Distant (A) and closer (B, C, and D) views of the lower portion of the tumor (within the black oval) show staining for MSH2. Strongly positive staining of the cells in the lower portion of the sebaceous epithelioma cells (red triangles) demonstrates preservation of MSH2 mismatch repair gene expression. Positive staining for MSH2 (black arrows) is also noted in the normal epidermis adjacent to the tumor (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
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case_images: PMC9941027_02_cureus-0015-00000033975-i11.jpg
case_images: FIG11
case_images: There was no loss of staining with MLH1 (Figure 10), MSH2 (Figure 11), and MSH6 (Figure 12).
case_images: Immunohistochemistry analysis demonstrates staining for MSH6 gene expression in a sebaceous epithelioma. Abbreviation: MSH6, MutS Homolog 6. Distant (A) and closer (B, C, and D) views demonstrate staining for MSH6 in the lower portion of the sebaceous epithelioma (within the black oval). The epidermis adjacent to the tumor also shows positive staining for MSH6 (black arrows). The staining of the tumor cells (black triangles) shows that the expression of the MSH6 mismatch repair gene is maintained (immunoperoxidase stain: A, x4; B, x10; C, x20; D, x40).
case_images: cureus-0015-00000033975-i12.jpg
case_images: PMC9941027_02_cureus-0015-00000033975-i12.jpg
case_images: FIG12
case_images: There was no loss of staining with MLH1 (Figure 10), MSH2 (Figure 11), and MSH6 (Figure 12).
case_images: PMC9941027_03
case_images: Sebaceous adenoma presenting as a papule on the nose of a 59-year-old male. Abbreviation: MLH1, MutL Homolog 1. Distant (A) and closer (B) views of the right nostril show a lesion of four years duration appearing as a 1 x 1-millimeter, flesh-colored, smooth papule with a central umbilication on the right nostril (black arrow and within the purple-inked oval). The man had germline-confirmed MLH1-associated Lynch syndrome; he had an intramucosal adenocarcinoma (pTis) arising focally in a tubular adenoma located in his ascending colon diagnosed at age 53 years. His family history was significant for colorectal cancer (mother had two primary neoplasms), kidney cancer (brother), liver cancer (mother and father), pancreatic cancer (mother), and rectal cancer (brother). The diagnosis of MLH1-associated Muir-Torre syndrome was established after the microscopic evaluation of the lesion, which was completely removed during the punch biopsy using a 2-millimeter biopsy instrument, showed a sebaceous adenoma; immunohistochemistry analysis of the sebaceous tumor unexpectedly showed preservation of the MLH1 mismatch repair gene.
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case_images: FIG13
case_images: Cutaneous examination of his face showed a 1 x 1-millimeter, flesh-colored, smooth papule with a central umbilication on the right nostril (Figure 13).