PMC5143717_01
Abdomen and pelvis computed tomography (CT) scan revealed a 6.0-centimeter mass (arrow) involving linea alba, bilateral rectus abdominis, and subcutaneous fat. The mass was not attached to any organs. Also noted was prominent left external iliac and inguinal lymphadenopathy.
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There was also prominent left external iliac and inguinal lymphadenopathy (Figure 1); the scan was otherwise unremarkable.
Whole body positron emission tomography-computed tomography (PET-CT) scan highlighted the abdominal wall mass (thick arrow) as well as left inguinal, paratracheal, and hilar (thin arrow) lymphadenopathy. However, no other lesions were identified.
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The abdominal wall mass and left inguinal lymphadenopathy were highlighted, as was paratracheal and hilar lymphadenopathy (Figure 2).
The abdominal wall mass (a) comprised small glands as well as large cystic spaces lined by cuboidal cells with eosinophilic, vacuolated or clear cytoplasm, and variably conspicuous nucleoli. The lymph node (b) showed glandular structures with morphology similar to that seen in the abdominal wall mass and residual lymphoid tissue in the background (hematoxylin-eosin staining, 200x).
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Biopsies of the abdominal wall mass (Figure 3(a)) and lymph node (Figure 3(b)) showed small fragments of adenocarcinoma and scant associated lymphoid tissue.
The serum CA19-9 level kept rising in spite of three cycles of XELOX and three cycles of gemcitabine/cisplatin and returned to the reference range following surgical resection of the abdominal wall mass.
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The mass continued to grow despite chemotherapy, and the serum CA19-9 level kept rising (Figure 4). The serum CA19-9 level normalized following surgery (Figure 4).
The tumor demonstrated a spectrum of serous neoplasia, with areas of serous cystadenoma representing the better differentiated component (a, b), papillary serous carcinoma with numerous Psammoma bodies representing the areas of high grade tumor (c, d), and solid sheets of poorly differentiated tumor cells representing the dedifferentiated component (e, f). These morphologic features were those of serous neoplasia with progressive dedifferentiation. Transition zones were present (g, h) (hematoxylin-eosin staining; (a), (c), (e), and (g) 40x; (b) 400x; (d) 600x; (f) 200x; (h) 100x).
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Sections from the spongy areas of the anterior abdominal wall tumor (Figures 5(a)-5(b)) showed small glands as well as variably sized cystic spaces lined by relatively monotonous cuboidal cells with clear cytoplasm and variably conspicuous nucleoli. Sections from the solid areas of the tumor (Figures 5(c)-5(d)) showed progressive decline in the size of the cystic spaces, and the epithelium became increasingly complex. In the most undifferentiated areas, the tumor was composed of sheets of discohesive cells with marked cellular atypia and prominent nuclear pleomorphism (Figures 5(e)-5(f)). However, all the histologic components of the large mass were capable of metastasis, as all components were present at lymph nodal metastatic foci; different components in juxtaposition were noted within the same lymph nodes (Figures 5(g)-5(h)). In summary, histopathologic examination of the tumor demonstrated a spectrum of serous neoplasia, with areas of serous cystadenoma representing the better differentiated component (Figures 5(a)-5(b)), papillary serous carcinoma with numerous Psammoma bodies representing the areas of high grade tumor (Figures 5(c)-5(d)), and solid sheets of poorly differentiated tumor cells representing the dedifferentiated component (Figures 5(e)-5(f)). Transition zones were present (Figures 5(g)-5(h)).
The tumor cells were strongly positive for CK7 (a), CK19 (b), CA19.9 (c), and MUC1 (d) (immunohistochemical staining, 100x).
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