Teaching Case

Obese 55-year-old man. In a pre-surgery CT (gastric bypass) appears a big diaphragmatic mass. He only refers sporadic abdominal pains and denies other symptoms.

CT: large mass located in right posterior subpleural space, homogeneous with attenuation similar to that of muscle and non-invasive.

Dynamic MRI Gd:
- arterial phase: shows discontinuous, nodular, peripheral enhancement
- portal venous phase: progressive peripheral enhancement with more centripetal fill-in.
- delayed phase: iso- and hyper-attenuating to liver parenchyma.
This tumour has a progressive and persistent enhancement (type 1).

DWI: hyperintense on diffusion-weighted imaging (DWI) and mostly hyperintense on ADC map.

Fat suppression and gradient echo sequences: No fat or haemoglobin degradation products are identified.

Primary tumours of the diaphragm are rare. These tumours occur at any age, although most frequently between the ages of 40 and 60 years [4].
Cystic tumours are the most common, but haemangiomas are extremely rare.
On the other hand, it is of vital importance to differentiate a primary diaphragmatic tumour from an invasive tumour or metastasis [2].

Most of the patients are asymptomatic. However, symptoms such as pain, cough, dyspnoea, or upper abdominal discomfort are observed [1].

Radiologically, most diaphragmatic tumours appear as smooth or lobulated soft tissue masses protruding into the inferior portion of the lung on chest radiograph [1].

On CT, a haemangioma appears as a homogeneous mass with attenuation similar to that of muscle. Calcifications occur most frequently in cavernous haemangiomas (30% of lesions).
The dynamic enhancement pattern is related to the size of its vascular space:
- arterial phase: typically shows discontinuous, nodular, peripheral enhancement (small lesions may show uniform enhancement).
- portal venous phase: progressive peripheral enhancement with more centripetal fill-in.
- delayed phase: iso- or hyperattenuating to liver parenchyma.

MRI [3]: haemangiomas usually have low or intermediate signal intensity on T1WI and some areas of high signal intensity comprise fat components, slow blood flow and haemorrhage, or a mixture of all 3.
On T2WI, haemangiomas have very high signal intensity (echo time greater than 88ms). It is advisable to carry out highly enhanced T2 studies for the characterisation of haemangiomas
T1 C+ (Gd): often shows peripheral nodular discontinuous enhancement which progresses centripetally (inward) on delayed images. Haemangiomas tend to retain contrast on delayed (>5 minutes) contrast-enhanced images.
DWI: hyperintense on diffusion-weighted imaging (DWI) even with high b-values due to slow blood flow and mostly hyperintense on ADC map.

Treatment [2]: when these tumours are symptomatic, a complete resection is the therapy of choice for the treatment. Sometimes resections makes it necessary to close or reconstruct the defects with synthetic or autologous tissue.