Presentation
Lump in left side of face.
Patient Data
Well circumscribed mass in the left parotid gland demonstrates hyperintense signal on T2WI, mild enhancement and low ADC value (approximately 600).
No extracapsular extension of enhancement is identified.
Lymph nodes within the field of view demonstrate no enlargement as per size criteria (subcentimeter in short axis).
The lesion in the left parotid gland has undergone core biopsy.
FDG avid nodes are identified above and below the diaphragm with involvement of the left parotid gland, right deep cervical chain, right axilla, retroperitoneum, and bilateral inguinal stations.
No extranodal involvement was identified.
Findings are consistent with stage 3 NHL.
Case Discussion
The parotid mass demonstrates features suggestive of lymphoma, particularly the low ADC value (approx 600).
The PET/CT reveals systemic involvement of nodal pathology.
Histology:
MICROSCOPIC EXAMINATION: A neoplastic follicular pattern is seen, associated with variable follicle expansion and loss of a well-defined mantle zone. Within the follicles, up to 12 centroblasts are seen per high-powered field (grade 2/WHO low grade).
Immunohistochemistry has been performed and shows positive staining with CD20 and PAX5. CD3 and CD5 highlight the background T cells with a similar staining pattern. CD5 is negative in the lesional cells. CD23 highlights the background follicular dendritic network, demonstrating some expansion of the follicles. BCL-2 and 6 both show positive staining in the follicles and patchy positive staining in the interfollicular zones. CD10 is positive. Cyclin D1, c-Myc, MUM1, SOX11 and LEF-1 are negative. The Ki-67 index shows some focal high proliferation rate up to 40%. EBER/EBV-ISH is negative.
Conclusion: Follicular lymphoma. In the sampled area features are of a Grade 2/WHO low-grade.