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The clinical value of imaging in primary cutaneous lymphomas: Role of high resolution ultrasound and PET-CT.

BACKGROUND:
Primary cutaneous lymphoma is a rare extranodal non-Hodgkin's lymphoma confined to the skin. The data on the imaging findings of primary cutaneous lymphomas are largely lacking and the current diagnosis is based on clinical and histopathological examination. With the advances in dermatological ultrasound and molecular imaging, newer perspectives in the evaluation of cutaneous lymphomas are available.


OBJECTIVE:
To review and describe the imaging findings in patient's with the diagnosis of primary cutaneous lymphoma.


METHODS:
A multicentric, retrospective observational study was undertaken in four countries to review the high resolution ultrasonography (HRUS) and fluorine 18-fludeoxyglucose positron emission tomography-computed tomography (PET-CT) imaging findings.


RESULTS:
We had 41 patients, Female:Male 1:4.1; mean age, 57 years; range, 13-94 years. High resolution ultrasonography of the primary cutaneous lesions revealed thickening of the dermis in all the cases and the lesions were hypoechoic without any calcifications or central necrosis. The sonographic appearances of the lesions were categorised into focal infiltrative, nodular, pseudonodular, and diffusely infiltrative patterns. Nodular and pseudonodular lesions were predominant in B cell lymphomas, while diffusely infiltrative lesions were more common in T-cell lymphomas. On colour Doppler imaging, the lesions were hypervascular. Whole body 18F-fludeoxyglucose PET-CT imaging of the patients revealed increased uptake of the metabolite in the lesions.


CONCLUSION:
Sonographic patterns based on high resolution ultrasonography provide early clues to the non-invasive diagnosis of primary cutaneous lymphomas and PET-CT is the recommended modality of imaging for staging and follow-up.


ADVANCES IN KNOWLEDGE:
High resolution ultrasound with colour Doppler and PET-CT imaging are complimentary to the clinical diagnosis of primary cutaneous lymphomas.