Suspected hydatid cyst of liver harbouring an aggressive desmoplastic small round cell tumour

Abstract

Among the group of small round cell tumours, there is a distinct and rare tumour known as desmoplastic small round cell tumour (DSRCT). DSRCT presents as multiple, widespread masses in the abdomen and pelvis and may be accompanied by extensive tumour implants throughout the peritoneum as the tumour is known to spread diffusely along serosal surfaces. We discuss a case of DSRCT in a 16-year-old boy who presented with abdominal pain since 2 years, a non-tender mass was palpable on the right upper quadrant of the abdomen, ultrasonographic and CT findings suggested hydatid cyst of liver. Laparotomy revealed multiple small peritoneal deposits along with a single mass in the liver. On histopathology, the lesion was found to be neoplastic and composed of predominantly clusters of small round blue cells, in a desmoplastic stroma; tumour cells were diffusely positive for cytokeratin, vimentin and neuron-specific enolase, thus confirming the diagnosis of DSRCT.

Figure 1

Contrast-enhanced CT scan showing involvement of the segment 2 of the left lobe of the liver.

Figure 2

(A) Small round tumour cells in a desmoplastic stroma, few cords of hepatocytes are also seen (H&E, ×100). (B) Clusters of small round blue tumour cell with scant cytoplasm surrounded by desmoplastic stroma (H&E, ×400).

Figure 3

Pan-cytokeratin positivity by tumor cells (pan-cytokeratin, ×100).

Figure 4

Vimentin positivity by tumour cells (vimentin, ×100).

Figure 5

Neuron-specific enolase (NSE) positivity by tumour cells (NSE, ×100).