A case of plasmacytoma of the pleural cavity is reported with massive malignant pleural effusion, which, most unusually, lacked monoclonal gammopathy, thereby making it difficult to distinguish from lymphoma. The pleural tumor and pleural effusion contained large mononuclear lymphoma-like cells with distinct nucleoli. Immunohistochemistry revealed neither lymphoma markers nor clonal cytoplasmic nor cell surface immunoglobulins. Tumor cells were stained with vimentin and the plasma cell markers, VS38c, CD138 (syndecan-1), and MUM1 antibodies. Bone marrow contained small amounts of tumor consisting of similar cells. Electron microscopy showed well developed rough endoplasmic reticulum and peripherally positioned nuclei with euchromatin. Flow cytometry of bone marrow revealed a minimal involvement of CD38-positive cells. Chromosomal analysis of marrow cells revealed a complex abnormal karyotype. A polymerase chain reaction demonstrated clonal re-arrangement of the immunoglobulin heavy-chain gene. The overall results indicate a clonal expansion of tumor cells with primitive plasma cell differentiation with the highly unusual feature of absent monotypic immunoglobulin. The study illustrates the need for a comprehensive array of techniques to distinguish such rare non-synthesizing and non-secretory plasmacytomas from lymphoma.

Sleep-related disordered breathing (SDB) and its influence on desaturation were examined in stable COPD patients with waking SpO2 > 90%. With respiratory inductance plethysmography, thoracic-abdominal respiratory movements for all events with more than 4% desaturation were analyzed in 26 patients. Types of SDB were confirmed by full polysomnography. Irregular breathing induced desaturation, while stable respiration continued during some desaturation events. Three types of altered ventilation were observed: hypoventilation, paradoxical movement and periodic breathing. An unusual type of paradoxical movement, with normal airflow despite progressive desaturation, was observed in REM sleep. Patients were divided into desaturation (15 patients) and non-desaturation (11 patients) groups. Daytime arterial blood gas, lung function values, and 6-min walking distance did not differ. Awake, mode, maximum and minimum nocturnal SpO2 were lower in the desaturation group. SDB-induced desaturation events in the desaturation group were more frequent (9.2+/-3.5 vs. 1.8+/-2.2 times), a greater SpO2 decrease (11.4+/-7.1% vs. 5.2+/-2.1%) and longer duration (73.2+/-34.8 vs. 18.8+/-39.0 min). Patterns of SDB in the desaturation group were hypoventilation (74.4+/-23.4%), paradoxical movement (10.2+/-14.5%), periodic breathing (12.1+/-18.3%) and unclassified (5.8+/-11.2%). These results reveal that lower SpO2 and SDB influence nocturnal desaturation in stable COPD patients.