Plasma cell neoplasms are clonal hematologic malignancies that represent 10% of all hematologic neoplasms. Incidence increases with advancing age and early diagnosis is rewarding due to great treatment amenability. Diagnosis of this malignancy requires a combination of clinical, biochemical, immunoelectrophoretic and bone marrow findings each with its due. Plasma cell rich effusions that do not form a part of diagnostic algorithm was identified as an incidental finding in 1 case of suspected plasma cell neoplasm and another confirmed case of plasma cell leukemia at our center and those cases are being described in this article. The value of plasma cell rich effusion as an associated finding in aggressive cases of plasma cell myeloma is being described here in correlation with the available literature. Plasma cell rich effusion in known or suspected cases of plasma cell neoplasms is a very rare event and is directly correlated with an adverse prognosis. It is hypothesized that the neoplastic cells can reach the pleural spaces by direct infiltration or can spread from adjacent skeletal lesions or via lymphatic obstruction; The effusions in myeloma patients can also be non myelomatous, related to systemic effects or complications. They can even be unrelated to plasma cell myeloma and may represent reactive effusions due to infectious causes such as tuberculosis, viral, fungal, or parasitic infections, or autoimmune conditions like SLE, post-vaccination reactions, chronic inflammatory diseases, or even post-surgical effusions. Immunocytochemical workup for kappa and lambda light chains could not identify restriction and proved inconclusive in both the cases. The article aims to add to the existing literature on the same topic.

Keywords: Plasma cell rich effusion, Kappa and lambda, Plasma cell neoplasms

Aardra Rageesh has completed her MD Pathology from Govt TD Medical College Alappuzha, Kerala state passed out in December 2025 at the age of 29. She has completed her MBBS from Govt Medical College Thrissur in the year 2021. She is currently awaiting to join Senior Residency at Govt TDMC Alappuzha. This is the first and only publication of the author in The Indian Journal of Pathology and Oncology in the year October 2025.