A unique presentation of an osteolytic chronic lymphocytic leukemia/small lymphocytic lymphoma as a helmet-shaped tumor.

Background: Cranial vault lymphomas (CVLs) are rare skull lesions, mostly caused by diffuse large B-cell lymphoma, a subtype of non-Hodgkin lymphoma (NHL). Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) extremely rarely causes cranial vault lesions. Herein, we report a case of a CLL/SLL causing a unique and extensive cranial vault lesion with a striking presentation of a helmet-shaped tumor, whose treatment with ibrutinib led to full bone regeneration. Case Description: A 63-year-old woman was admitted to our hospital for the continuation of treatment of CLL/SLL, which presented with hypercalcemia, generalized lymphadenopathy, and osteolytic lesions of Th10, Th11, and L2 vertebrae. An initial head computed tomography (CT) scan, performed due to psychomotor impairment, showed an extensive CVL. Despite therapy, a control CT scan showed progression of the CVL-shaped like a helmet, destroying the occipital, both parietal and a part of the frontal bone, with the effacement of the external table and somewhat preserved internal table. Successful therapy with ibrutinib led to full bone regeneration. Conclusion: Striking CVL presentations like the extensive permeative dissolution of the whole cranium rarely occur, especially in otherwise indolent types of NHL. Nevertheless, full bone regeneration and recovery are possible with modern treatment options, given adequate analysis is obtained beforehand. In case of a discrepancy between core-needle biopsy or fine-needle aspiration findings and the clinical picture, a surgical biopsy is warranted.