2026-07-11 | Pulmonary coexistence of immunoglobulin light chain amyloidosis and light chain deposition disease: A case report.

We report the case of a 73-year-old woman with diffuse pulmonary cysts and multiple nodules incidentally detected during the follow-up for chronic liver disease. High-resolution computed tomography revealed numerous thin-walled cysts, predominantly in the lower lobes, with randomly distributed nodules. Pathological evaluation of the surgical lung biopsy specimens revealed nodular deposits of eosinophilic, amorphous material with peribronchiolar lymphoplasmacytic inflammation and identified pulmonary mucosa-associated lymphoid tissue lymphoma. Congo red staining revealed coexisting positive and negative foci within a single nodule, whereas immunohistochemistry showed kappa (κ) light chain positivity in both. Laser microdissection with liquid chromatography-tandem mass spectrometry identified a κ light chain dominant signature with amyloid signature proteins in the Congo red-positive region, consistent with immunoglobulin light chain amyloidosis (AL) κ-type, and abundant κ light chain peptides without amyloid signature proteins in the Congo red-negative region, consistent with non-amyloid κ light chain deposition. Systemic evaluation revealed no extrapulmonary amyloid or light-chain deposition, whereas Sjögren disease was confirmed by serological testing and minor salivary gland histology. The patient was managed conservatively with surveillance and remained clinically and radiographically stable without disease progression for approximately 1 year. Pulmonary AL and light-chain deposition are rare lung disorders, and pathologically proven pulmonary coexistence is rare. This case may help delineate the clinicopathological features of pulmonary monoclonal light chain deposition disorders.

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2026-07-08 | Clinicopathologic characterization of plasma cell neoplasms with IGH::CCND3.

Plasma cell neoplasms (PCNs) harboring IGH::CCND3 (t(6;14)) are rare (<1% of PCNs). We sought to study these cases, as they have not been studied as a distinct entity, and their clinicopathologic features are not well characterized. Cytogenetics databases were searched for positive IGH::CCND3 interphase fluorescence in situ hybridization (FISH) results in plasma cell neoplasms. We analyzed the clinical, morphologic, immunophenotypic, and cytogenetic features of these cases and evaluated the utility of cyclin D3 immunohistochemistry (IHC) for identifying these neoplasms. Sixteen patients were identified, presenting with multiple myeloma (n = 9), monoclonal gammopathy of undetermined significance (n = 3), smoldering myeloma (n = 2), plasma cell leukemia (n = 1), and amyloid light chain amyloidosis (n = 1). Median age at diagnosis was 68.9 years. Most cases showed lymphoplasmacytoid morphology (63%, 10/16), with frequent CD20 expression (53%, 8/15) and aberrant expression of CD56 (71%, 10/14) and CD117 (69%, 9/13). Monosomy 13 was the most frequent concurrent cytogenetic abnormality (50%, 7/14). Cyclin D3 IHC showed nuclear expression in plasma cells in all tested patients (11/11). Background erythroid precursors and megakaryocytes also showed variable positivity. When performed as a dual immunostain with CD138, cyclin D3 served as a highly sensitive and specific method for detecting these neoplastic plasma cells. IGH::CCND3 PCNs frequently exhibit lymphoplasmacytoid features and CD20 expression, resembling the more common t(11;14) PCNs. Cyclin D3 IHC is an effective surrogate for the t(6;14) translocation in PCNs. We recommend using cyclin D3 IHC in the workup of PCNs with lymphoplasmacytoid morphology but negative cyclin D1 to appropriately trigger reflex FISH testing in positive cases and rescue them from the "partner-negative" category.

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2026-07-01 | Waldenström macroglobulinemia-associated renal AL amyloidosis: a case report and literature review.

Waldenström macroglobulinemia (WM) is a rare indolent B-cell lymphoma, characterized by lymphoplasmacytic infiltration of bone marrow and the existence of monoclonal IgM in circulation. Renal AL amyloidosis is an uncommon complication of WM, and its treatment is an enormous challenge to clinicians. This report describes a 71-year-old woman who presented with a 10-month history of recurrent bilateral lower extremity edema and a progressive fatigue. Physical and laboratory examinations revealed serum monoclonal IgMλ, nephrotic syndrome, moderate anemia and mild enlargement of bilateral inguinal superficial lymph nodes. Bone marrow aspiration demonstrated clonal lymphoplasmacytic infiltration, lymph node biopsy was consistent with lymphoplasmacytic lymphoma, and peripheral blood testing confirmed the presence of the MYD88 L265P mutation. Renal biopsy confirmed the diagnosis of renal AL amyloidosis, evidenced by Congo red-positive amorphous deposits with λ light chain restriction in glomeruli, interstitium, and small arterial walls. Following multidisciplinary consultation, the patient was treated with the bendamustine plus rituximab (BR) regimen. After three cycles, the patient achieved partial hematologic response (serum IgM levels decreased from 23.7 g/L to 7.1 g/L) with slight improvement of proteinuria (urine protein excretion decreased from 18.2 g/d to 15.0 g/d). However, during the subsequent treatment, the patient developed a severe pulmonary infection that led to death. This case underscores two critical points: First, patients with WM should be routinely tested for serum and urine monoclonal free light chains, as they can exist in WM at a high proportion and can independently induce monoclonal gammopathy-associated renal diseases, including renal amyloidosis. Second, for WM patients with renal AL amyloidosis, choosing BR regimen as the first-line treatment is reasonable. However, during the treatment process, it is essential to closely monitor and actively prevent the adverse effects of this regimen, particularly severe infections which may have fatal consequences.

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