Subphrenic hydatid cyst at upper surface of spleen

Case contributed by Dr Muhammad Shoyab

Presentation

Left upper abdominal pain, fever. Blood count - neutrophils high, eosinophils normal. Ultrasound - fatty liver, hepatitis, pleural effusion. CT Chest - bilateral basal pneumonia, left-sided pleural effusion, left-sided subphrenic fluid collection, hiatal hernia. Serum markers - CA 19-9 raised, alkaline phosphatase high and rising.

Patient Data

Age: 60 years
Gender: Female

MRI Upper Abdomen

MRI

There is a large thick-walled cystic mass at upper part of stomach bed, abutting upper surface of spleen, apparently originating from here. It displaces stomach leftwards (herniated) and left hemidiaphragm upwards (elevated). The cyst contains numerous internal thin septations, producing honeycomb appearance. There are multiple signal void foci, which may represent protoscolices.

There is also a thick-walled daughter cyst abutting its lower posterior wall, containing low intensity sediments in its dependent part.

No mural or internal enhancement of primary or daughter cyst is present.

Left hemidiaphragm elevated. Moderate pleural effusion on left side.
Volume loss & hyperintense appearance involving basal segments of left lung, representing atelectasis.

Cardiac end, fundus & upper body of stomach herniated through esophageal hiatus into right side of posterior mediastinum — sliding hiatal hernia.

Tiny signal void calculus at neck of gall bladder.

Key Images (MRI)

Annotated image

Honeycomb appearance of the cyst, due to numerous internal septations. Thick-walled daughter cyst, itself having internal septations and sediments.

Sliding hiatal hernia.

Tiny calculus at neck of gall bladder.

Case Discussion

A cystic lesion in the peritoneal space can be one of a handful of possibilities, but the discrete presence of a daughter cyst inside sways the imaging diagnosis in favor of hydatid. This is coupled with the high and gradually rising levels of alkaline phosphatase, which has been suggested as a biomarker for hydatid activity 1,2. Presence of a daughter cyst at its periphery classifies it as a type-IIa. Other characteristic features present here include numerous internal septations, signal voids that may represent protoscolices, as well as absence of lymphadenopathy.

It is interesting that such a large lesion was missed on two ultrasound examinations about two weeks apart. This may be because the lesion with its internal sediments appeared to be the stomach with food content.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.