Computed tomography in hematologic malignancies of paranasal sinuses

Magnetic resonance imaging (MRI) and dynamic MRI evaluation of extranodal non-Hodgkin lymphoma in oral and maxillofacial regions

OBJECTIVE

The purpose of this study was to evaluate the diagnostic value of magnetic resonance imaging (MRI), especially dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), in extranodal non-Hodgkin lymphoma (NHL) of oral and maxillofacial regions.

STUDY DESIGN

Thirteen cases with extranodal NHL were examined using MRI. T1-weighted images (T1WI) and T2-weighted images (T2WI) or short TI inversion recovery (STIR) images were obtained in all cases. Contrast-enhanced images and DCE-MRI were acquired in 10 and 7 cases, respectively. On DCE-MRIs, we analyzed the parameters as follows: contrast index at maximal contrast enhancement (CImax), maximum contrast index (CI) gain/CImax ratio, and washout ratios (WR(300), WR(600), and WR(900)) at 300, 600, and 900 seconds after contrast medium injection.

RESULTS

The signal intensity of all lesions was hypointense to isointense on T1WIs and showed variable contrast enhancement patterns. On T2WIs and STIR images, the signal intensity was isointense to hyperintense in almost all cases. Analysis of DCE-MRI parameters in extranodal NHLs resulted in the identification of 4 types of CI curves according to CImax and WR: (1) CImax greater than 2.0 and WR(900) greater than 40%, (2) CImax greater than 2.0 and WR(900) less than 40%, (3) CImax less than 1.5 and WR(900) greater than 40%, and (4) CImax less than 1.5 and WR(900) greater than 40%.

CONCLUSIONS

The signal intensities on MRI were not specific to extranodal NHL and resembled those of other tumor types. When CImax was less than 1.5 or WR900 was less than 40%, these parameters contributed to diagnosis in extranodal NHLs.

Sinonasal Non-Hodgkin's Lymphoma with Skull Base Involvement

Non-Hodgkin's lymphoma (NHL) is a rare tumor of the skull base. As the incidence of primary central nervous system (CNS) lymphoma has increased, atypical presentations involving the skull or cranial base exclusively have been reported. In immunocompetent patients with no previous history or predisposing factors, the diagnosis of primary NHL of the skull base may be delayed. We present four cases of nasal and paranasal sinus NHL with both skull base and intracranial involvement in immunocompetent patients. Clinicopathologic correlation suggests that cranial base and intracranial involvement with NHL represents advanced-stage primary sinonasal disease. Surgical biopsy before definitive treatment is recommended. Radiation therapy provides local control; adjuvant chemotherapy after primary radiation therapy may be required for recurrent disease.

MRI of lymphomas of the orbits and the paranasal sinuses

PURPOSE

The purpose of this study was to point out MR characteristics of non-Hodgkin lymphomas of the orbits and the paranasal sinuses and the benefit of fat-suppressed contrast-enhanced sequences.

METHOD

The MR images of 16 patients with lymphoma of the orbits and the paranasal sinuses were retrospectively analyzed for signal intensity, contrast enhancement, bone destruction, and mass effect. The findings were confirmed by means of biopsy (Stage IE disease) or follow-up imaging after chemotherapy (Stage IV disease).

RESULTS

MRI clearly delineated the extension of the lymphomas. On the T1-weighted images, the signal intensity of the lymphoma was hypointense compared with the gray matter of the brain in 12 cases and intermediate in 4 cases. The T2-weighted fast SE images showed a hyperintense signal in 12 cases, intermediate in 3 cases, and even hypointensity in 1 case. All lesions enhanced after intravenous Gd-DTPA administration, reliably visible in the T1-weighted fat-suppressed sequences but not visible in three cases in the T1-weighted SE sequences. Bony wall destruction was evident in cases with paranasal but never in isolated orbital lymphoma.

CONCLUSION

While extension of lymphoma can be accurately described by MRI, a specific diagnosis is not achievable on the basis of signal intensities and enhancement patterns alone. Therefore, at least in cases of suspected Stages IE and IIE, biopsy proof is needed. Fat-suppressed contrast-enhanced sequences possess the highest detection rate and should therefore always be applied.

B-cell non-Hodgkin's lymphoma of the paranasal sinuses

Primary nasal, paranasal, oral and pharyngeal (NPOP) lymphoma, thought to be a distinct entity among childhood lymphomas, may present with a wide variety of common ENT symptoms such as nasal obstruction, rhinorrhoea, epistaxis or sinusitis. The diagnosis may only be recognized when the disease results in symptoms such as visual loss, facial paraesthesia or lymphadenopathy, or systemic symptoms, such as fatigue, bone pain or abdominal pain. Full radiological assessment plays a vital part in making the diagnosis and planning treatment. Computerized tomography (CT) gives excellent bony detail but magnetic resonance imaging (MRI) using T2-weighted images, allows differentiation of mucosal thickening and retained sinus secretions from the tumour. Extension into the surrounding spaces and the cranial fossa is best assessed by coronal and sagittal T2 images. MRI is the best technique for follow-up because no radiation is involved and better soft tissue delineation improves the distinguishing of tumour from fibrosis.