case_images: PMC11392682_01
case_images: The patient's imaging features during whole course of the disease in abdominal and pelvic enhanced CT. (A). Preoperative Abdominal and Pelvic Enhanced CT in June, 2023. Multiple soft tissue masses with blurred edge were observed in the abdominal cavity(white arrow). After contrast enhancement, the masses showed obvious uneven enhancement, the largest one was about 19.5*16.8cm. Massive ascites and multiple retroperitoneal enlarged lymph nodes were seen in the abdomen and pelvis. (B). Postoperative Abdominal and Pelvic Enhanced CT in August, 2023. Ascites was still in the pelvic cavity. (C). Abdominal and Pelvic Enhanced CT in September, 2023. Interim assessment of chemotherapy show disease progression(tumors recurred as shown by white arrow). (D). Abdominal and Pelvic Enhanced CT in November, 2023. One month after initiating ALKi treatment, assessment showed significant tumor shrinkage and reduction in ascites(white arrow). ALKi, anaplastic lymphoma kinase inhibitor.
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case_images: Figure 1A ). Following a multi-disciplinary team (MDT) discussion, the patient underwent exploratory laparotomy, abdominal mass resection, partial jejunal resection, jejunal anastomosis, ileocecal resection, and ileocolonic anastomosis (postoperative enhanced CT are shown in s). Imaging examination revealed multiple nodules in the abdomen and pelvis, with sizes up to 2.2x1.7 cm ( Figure 1C ). Subsequent abdominal and pelvic enhanced CT scans in November 2023 revealed significant tumor shrinkage and reduction (the maximum tumor diameter decreased from 35.6cm to 5.1cm), along with a notable decrease in ascites ( Figure 1D ).
case_images: Surgical specimen and pathological examination. (A) Gross examination revealed a massive tumor weighing 8kg and adjacent organ involvement. (B). Hematoxylin and Eosin staining showed the existence of both spindle cells and epithelioid cells. (C). IHC staining for ALK revealed positive expression around the nuclei of tumor cells. (D, E). IHC staining showed positive for desmin (D) and SMA (E). (F). FISH revealed splitting signals inside tumor cells (As indicated by the white arrow), confirming the presence of ALK rearrangement. IHC, immunohistochemical; ALK, anaplastic lymphoma kinase; FISH, fluorescence in situ hybridization.
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case_images: Postoperative pathology ( Figure 2A ) revealed that the tumors originated from intra-abdominal mesenchymal tissue, with sizes of 35x25x13 cm, 14x11x9 cm, and 5x3x3 cm respectively. The tumors contained spindle cells and epithelioid cells simultaneously, with lamellar necrosis, mitotic figures of 2-3/10 HPF (high power field), and myxoid stroma ( Figure 2B ). Immunohistochemical (IHC) staining results ( Figures 2C-E ) were as follows: ALK, p16, p53, CDK4, desmin, SMA, S-100, CD34, CD30, CD68, WT1, Calretinin, D2-40, and Ki-67 (approximately 30%) were positive, while CK, MDM2, CD117, DOG-1, Myogenin, and EMA were negative. Meanwhile, ALK rearrangement was confirmed via fluorescence in situ hybridization (FISH) as shown in  Figure 2F .