Introduction: Multiple myeloma (MM) is a rare hematologic malignancy characterized by uncontrolled plasma cell proliferation. About one-third of MM patients develop maxillary advanced-stage lesions, which are usually associated with poorer survival outcomes, serving as prognostic indicators of disease progression. The aim of this report is to describe a case of an extensive, aggressive and invasive osteolytic lesion of the mandibular angle in a patient with a complex medical history.

Methods: An 80-year-old female patient with a medical history of multiple vertebral fractures, paroxysmal atrial fibrillation, cardiac disease, hypotension, arteriopathy, type 2 diabetes mellitus, dysthyroidism, dyslipidemia and obesity presented to our attention with painful swelling of the left mandibular angle, also including the submandibular area. Radiography showed a radiotransparent osteolytic lesion with irregular borders, which incorporated the left mandibular angle and inferior mandibular border. CT was required to better evaluate the dimensions of the lesion. Considering that performing an FNA was not possible, under local anesthesia, a mucoperiosteal flap was elevated to reveal the mandibular ramus and access to the lesion for an incisional biopsy. Specimens were sent for histopathological examination.

Results During surgery, the patient experienced episodes of atrial fibrillation and was sent to Cardiology for a specialist check. The histological exam led to diagnosis of MM with extensive plasma cell infiltration, and then the patient was sent to the Hematology Section for an adequate treatment. The patient was lost at the follow-up.

Conclusions: Biopsy of malignant extensive osteolytic lesions in patients with a complex medical history is particularly challenging because of the high intra- and post-operative risks. When diagnosed, management becomes complicated due to systemic complications, which lead to difficulties in implementing effective therapy and adequate follow-up.