Diagnostic pitfalls of nonsecretory myeloma manifesting as multiple foci of periosseous plasmacytomas

Nonsecretory myeloma, which comprises 1–5% of all myelomas, is a variant of plasma cell myeloma. It is defined as symptomatic myeloma without detectable monoclonal immunoglobulin levels on serum or urine immunofixation electrophoresis. Here, we report two cases of nonsecretory plasma cell myeloma that manifested as multi-foci periosseous plasmacytomas. Due to the inability to detect monoclonal immunoglobulin on serum or urine immunofixation electrophoresis and the lack of evidence of clonal plasma cells in the bone marrow, it was difficult to establish an early, accurate diagnosis. Misdiagnosing or mislabeling symptomatic myeloma patients with plasmacytoma results in the delay of their systemic treatment. Therefore, comprehensive imaging studies, the detection of free light chains, and histopathological confirmation from different sites and time points are necessary

Metastatic primary neuroendocrine carcinoma of the breast (NECB)

Neuroendocrine carcinoma of the breast (NECB) is a subtype of breast cancer. The diagnostic criteria of primary NECB were established in 2003 and updated in 2012. It is a rare entity, and few studies have reported the histogenesis, immunohistochemistry for a pathological diagnosis, clinical behavior, therapeutic strategies, and the prognostic factors. Because of the rarity of this disease, consistent diagnostic criteria will remind physicians of this disease when making a differential diagnosis to enable a timely diagnosis and prompt treatment. Herein, we report a case of primary NECB who presented with a history of right hip pain arising from an osteolytic lesion in the right acetabulum and ischium. The course of investigation started with metastasis in the right hip and concluded with a diagnosis of NECB. In addition to the case report, we also conducted a literature review