Brought by his parents due to a new abdominal distension, having complained of intermittent abdominal pain that would wake him from sleep. Systemic fever up to 38.5°C. 2-Kg weight loss during the past 2 weeks.

At the ER, he looked pale. The liver was palpated 4 cm below the costal arch. Right upper quadrant tenderness elicited. A single soft axillary node was palpated on the right.

Lab exams remarkable for elevated hepatocellular enzymes and normocytic hypochromic anemia.

Ultrasound demonstrated a huge hepatic mass, as did the CT and PET-CT scans. The mass was 30% larger on the PET-CT study, attributed to intralesional hemorrhage. This was verified on a repeat US (not shown).

Alpha fetoprotein 2.2 ng/mL (normal), CMV IgG positive.

Histopathology report of a biopsy obtained from the mass:
Tiny fragments from a liver mass, compatible with a malignant mesenchymal tumor.

A port was inserted and the patient was started on chemotherapy.

Histopathology report from the right lobectomy specimen:
Small foci represent less than 2% of the mass volume of residual undifferentiated sarcoma composed of large pleomorphic stromal cells, present at the edge of the tumor, focally infiltrate the sinusoids and stain very weakly and scattered cells positive for CD31 and desmin. KER MNF116, CD34, SMA, myogenin, and ERG negative in the pleomorphic cells.
The mass shows extensive treatment effect, with hyalinosis, abundant siderophages, necrosis, and residual bile ducts, thick walled vessels, and groups of hepatocytes mixed with pleomorphic cells.
India-inked surgical margin free of tumor in the sections examined. India-inked margins of the diaphragm shows fragment of muscle focally necrotic and tissue with marked treated artifacts. It is not possible to define residual tumor in these areas. Liver parenchyma preserved. Gallbladder unremarkable.

In light of the finding of pleomorphic cells and in light of the immunohistochemical assay results, the remnants are compatible with undifferentiated embryonal sarcoma.