PMC5500437_01
High-grade neuroendocrine component. High-grade neuroendocrine component with intermediate-sized cells arranged in solid sheets. The cells have scant cytoplasm and prominent nucleoli in addition to brisk mitotic activity and abundant apoptotic bodies. (Hematoxylin and eosin, 200X)
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F1
The initial endometrial biopsy demonstrated solid sheets of round, intermediate-sized, discohesive cells with open chromatin and prominent nucleoli (single or multiple), as well as numerous mitotic figures and apoptotic bodies (Figure 1).
Mesonephric adenocarcinoma component. Mesonephric adenocarcinoma component composed of tubules and duct-like structures filled with eosinophilic secretions. Occasional cystic dilatation of the tubules is seen. (Hematoxylin and eosin, 100X)
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F2
Small foci showed cystically dilated tubules (Figure 2).
Different morphologic patterns of mesonephric component. Higher magnification shows small tubules lined by cuboidal to low columnar cells with conspicuous nucleoli. The intraluminal contents were either densely eosinophilic (A) or composed of necrotic cellular debris (B). Note the mild chronic peritumoral inflammatory infiltrate (A) and the subtle myxoid/edematous stromal changes (B). Areas with elongated, cleft-like spaces and occasional intraluminal papillary formations (C) and foci displaying cytomorphologic features reminiscent of endometrioid differentiation characterized by tubules with taller cells and pseudostratified nuclei (D) compared to the classic mesonephric component in the upper left corner of the image. (Hematoxylin and eosin, 400X and 200X)
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F3
When present, intraluminal contents varied from eosinophilic hyaline material to necrotic with cellular debris, the latter being more common (Figure 3). Multifocally, the glands/tubules displayed slightly taller cells with pseudostratified nuclei, reminiscent of endometrioid glands (Figure 3).
Juxtaposition of high-grade neuroendocrine and mesonephric carcinomas. There is intermingling of both components, but they are clearly distinct from one another. (Hematoxylin and eosin, 200X)
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F4
The two major tumor components (superficial solid and deep tubular) intermingled in several areas of juxtaposition; however, obvious merging of these components was not seen (Figure 4).
Small lobules of mesonephric tubules with bland cytologic features. Small lobules of mesonephric tubules showing more bland cytologic features present in the deep cervical wall (A) and intermixed with the bulk of the tumor (B). Compare the cytology of these areas to the adjacent mesonephric adenocarcinoma in the upper right corner (A) and left bottom corner of inset (B). (Hematoxylin and eosin, 200X and 400X)
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F5
The tubules did not display intraluminal content or dense hyaline material; no necrotic debris was seen (Figure 5).
Polypoid tumor protruding into endocervical canal. Polypoid tumor protruding into the endocervical canal formed by the high-grade neuroendocrine carcinoma, and deeper tumor infiltrating into the cervical wall composed of the mesonephric component. (Hematoxylin and eosin, 10X)
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F6
As previously noted, the intramural portion of the tumor was composed of the mesonephric carcinoma extending close to the endocervical surface, while the neuroendocrine carcinoma emerged from the superficial cervical stroma and formed an exophytic polypoid lesion protruding into the endocervical canal (Figure 6).
Immunohistochemistry results. Mesonephric component (A) showing negative ER (C), PR (E), and synaptophysin (G). Rare tubules were chromogranin-positive (I) and CD10 showed the typical intraluminal pattern of staining (K). Patchy positivity for GATA-3 was seen mainly in the peripheral areas of the tumor (M); diffuse positivity for PAX-8 (O). P16 positivity was focal (Q). The neuroendocrine component (B) was negative for ER and PR (D and F, respectively), whereas synaptophysin was strong and diffuse (H). Chromogranin was focal (J); CD10 was entirely negative (L). GATA-3 and PAX-8 both showed weak, focal staining (N and P, respectively). P16 was diffusely and strongly positive (R).
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F7
ER, PR, synaptophysin, CD56, and TIF-1 were negative (Figure 7).
HPV 16 and HPV 18 PCR results. Both mesonephric and neuroendocrine components were negative for HPV 16 (A) and HPV 18 (B) subtypes. Compare to positive controls for HPV 16 and 18 (CaSki and HeLa, respectively).. MC, mesonephric adenocarcinoma component; NEC, neuroendocrine carcinoma component; HeLa, HPV 18-positive cervical carcinoma cell line; CaSki, HPV 16-positive cervical carcinoma cell line; neg, negative control
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F8
Non-synonymous somatic mutations and amplifications. Non-synonymous somatic mutations and amplifications were identified in the mesonephric carcinoma and HGNEC components using targeted next-generation sequencing. Each row represents one tumor component; altered genes are reported in columns. Alteration types are color-coded according to the legend.. SNV, Single Nucleotide Variant
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F9
It should be noted, however, that the low tumor purity in the mesonephric carcinoma limited the detection of variants that might be present at frequencies below the variant calling threshold (2% for known hotspot mutations, 5% for other variants) (Figure 9).
FISH on mesonephric and neuroendocrine components. FISH on the mesonephric and neuroendocrine components showed the mesonephric component (A) and the neuroendocrine component (B). Both demonstrated high level amplification of MYCN gene in 96% and 100% of the analyzed cells, respectively. The number of green signals was too numerous to count; therefore, a formal ratio of LSI:CEP signals was not determined. Green represents the LSI MYCN probe. Red represents the chromosome 2 centromeric probe.. FISH, Fluorescence in situ Hybridization; LSI, Locus-Specific Identifier; CEP, Chromosome Enumeration Probe
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F10
The green signals corresponding to the LSI MYCN probe were too numerous to count in both components; thus, a formal ratio of LSI:CEP signals was not determined (Figure 10).