case_images: PMC4132276_01
case_images: Clinical presentation of Case #1: Preoperative CT-scan (A) of the tumour in the lower left abdominal wall. Macroscopic presentation of the surgical specimen (B); central parts of the tumour are well delimited ('core'); the path of the primary laparoscopy is visible. The tumour infiltrated the abdominal skeletal muscles but did not extra into the abdominal cavity.
case_images: 1472-6890-14-36-1.jpg
case_images: PMC4132276_01_1472-6890-14-36-1.jpg
case_images: F1
case_images: A CT-scan unmasked a 4.2 x 2.7 x 7 cm hypodense (50HU) solid mass in the painful abdominal region [Figure  1A]. On gross examination the 13 x 10.5 x 6 cm specimen contained a 7 x 3.5 x 3.1 cm tumour with whitish/pale yellow cut surfaces [Figure  1B].
case_images: Histopathology of Case #1: The tumour shows patches of higher differentiated atypical lipomatous tissue (A) but mostly displays only poorly differentiated spindle-shaped cells (B). Prominent areas with myofibroblastic morphology were noticed (C) and immunohistochemistry was positive for Desmin (D) and Actin.
case_images: 1472-6890-14-36-2.jpg
case_images: PMC4132276_01_1472-6890-14-36-2.jpg
case_images: F2
case_images: Haematoxylin and eosin (HE) staining showed a neoplasm with high cellularity and mostly spindle-shaped cells arranged in storiform patterns (Figure  2B).
case_images: Molecular hallmarks of Case #1: Immunohistochemistry demonstrates co-overexpression of CDK4 (B) and MDM2 (C) in both the poorly and higher differentiated areas (A: HE-staining of corresponding region). Fluorescence in situ hybridisation shows strong amplification of the MDM2 locus as underlying genetic alteration (D; Green: MDM2 probe, Red: Chromosome 12 reference probe). The features are characteristic of dedifferentiated liposarcoma.
case_images: 1472-6890-14-36-3.jpg
case_images: PMC4132276_01_1472-6890-14-36-3.jpg
case_images: F3
case_images: Neoplastic giant cells with nuclear vacuoles were present (Figure  3) and IHC stainings for CDK4 and MDM2 were positive (3B, C).
case_images: PMC4132276_02
case_images: Histopathology and molecular hallmarks of Case #2: The tumour showed heterogeneous morphology. Most cells were spindle-shaped but giant cells with segmented nuclei were also present. Focally, transitions into higher differentiated lipomatous tissue were noticed (A). Other areas were of osteoblastic/osteosarcomatous (B) and fibrosarcomatous appearance (C). Fluorescence in situ hybridisation of the MDM2 gene revealed highly amplified clusters in the lipomatous (D, left), fibrosarcomatous and the osteosarcomatous regions (D, right).
case_images: 1472-6890-14-36-4.jpg
case_images: PMC4132276_02_1472-6890-14-36-4.jpg
case_images: F4
case_images: HE stainings showed a mesenchymal proliferation with high cellularity and mixed morphology (Figure  4): The cells were mostly of spindle-shaped appearance with high pleomorphy. Transitions into more differentiated fatty tissue were found (Figure  4A) as well as areas with osteoblastic/osteosarcomatous (4B) and fibrosarcomatous appearance (4C).