Characteristics of cranial vault lymphoma from a systematic review of the literature

Background:

Cranial vault lymphomas are rare and their clinical features are often similar to those of cranial vault meningiomas. The objective of this review was to identify the features helpful for differentiating lymphomas of the cranial vault, from meningiomas which were the most common diagnosis before the definitive pathological diagnosis.

Methods:

The inclusion criterion was a histologically proven malignant lymphoma initially appearing in the calvarium. We conducted a literature search of the electronic PubMed and Ichushi-Web databases up to June 1, 2020. Cranial vault lymphoma that was diagnosed after an original diagnosis of lymphoma in a nodal or soft-tissue site was excluded from the study. Descriptive analyses were used to present the patient characteristics.

Results:

A total of 111 patients were found in 98 eligible articles. Almost all studies were case reports. The most common symptom was a growing subcutaneous scalp mass (84%) present for a mean duration of 5.9 months before the patient presented for treatment in analyzable cases; this fast growth may distinguish lymphomas from meningiomas. The tumor vascularization was often inconspicuous or poor, unlike well-vascularized meningiomas. A disproportionately small amount of skull destruction compared with the soft-tissue mass was observed in two-thirds of the analyzable cases.

Conclusion:

This qualitative systematic review identified several features of cranial vault lymphomas that may be useful in differentiating them from meningiomas, including a rapidly growing subcutaneous scalp mass, poor vascularization, and limited skull destruction relative to the size of the soft-tissue mass.

B cell lymphoma with IRF4 rearrangement: A clinicopathological study of 13 cases

Interferon regulatory factor 4 (IRF4) rearrangement is commonly detected in patients with a range of lymphoproliferative malignancies, including myelomas, large B cell lymphomas and low-grade B cell neoplasms. However, IRF4 rearrangement is generally a relatively rare finding in these latter two cancer types. In the present article, we describe and summarize the clinicopathological and genetic features of 13 cases of B cell lymphoma with IRF4 rearrangement, including 12 cases of large B cell lymphoma and one case of low-grade lymphoma exhibiting such rearrangement. These cases were detected in six females and seven males between 14 and 71 years of age. From a morphological perspective, large B cell lymphoma tumors included in this analysis exhibited large neoplastic cells in diffuse or follicular patterns, while the case of low-grade lymphoma mainly composed of small lymphocytes. All analyzed cases exhibited a split in the IRF4 gene consistent with IRF4 translocation. Three of six analyzed large B cell lymphoma cases harbored IGLL5 mutations. Mutations in SAMHD1 were detected in the low-grade lymphoma with IRF4 rearrangement case. In summary, our results offer further insight into the morphological and molecular heterogeneity of cases of B cell lymphoma exhibiting IRF4 rearrangements.