Soft tissue masses in patients with multiple myeloma - A fine-needle aspiration study of 30 cases with flow cytometry and clinical correlation

BACKGROUND. To the authors' knowledge, the prognostic significance of plasm a cell cytology in soft tissue (ST) masses from patients with multiple myel oma (MM) is unknown. Myeloma patients usually are monitored by bone marrow (BM) aspirates and biopsies to assess plasma cell differentiation, tumor bu rden, and response to treatment. Monitoring of ST lesions by fine-needle as piration (FNA) is not performed routinely. The objective of the current stu dy was to examine ST masses in MM patients using FNA and to classify and de termine the prognostic significance of MM in these lesions based on cytolog ic features. METHODS. FNAs of 30 ST masses from 27 patients with a history of MM were ex amined for disease involvement. In the patients with MM, the cytologic feat ures were evaluated and the lesions were graded as low grade, intermediate grade, or high grade based on the classification of Bard et al. for MM in B M specimens. Concurrent BM samples as well as cytogenetic and flow cytometr ic results also were reviewed. RESULTS. Twenty-seven of the FNA specimens (90%) were positive for MM, and three specimens (10%) were negative (one case each of lipoma, keratinous cy st, and aspergillosis). Among the MM cases, 5 (18.5%) were low grade, 15 (5 5.6%) were intermediate grade, and 7 (25.9%) were high grade (blastic MM). Simultaneous BM involvement was present in 23.5% of low-grade MM (4 of 17 c ases), 35.3% of intermediate-grade MM (6 of 17 cases), and 71% of high-grad e MM (5 of 7 cases). Clinically, 10 of 24 patients (42%) died within 9 mont hs (median, 2 months). Patients with high-grade myeloma (blastic MM) in ST masses appeared to have worse survival; 43% (3 of 7 patients) died by a med ian time of 2 months, compared with 12% of patients with low-grade and inte rmediate-grade MM (2 of 17 patients). CONCLUSIONS. FNA of ST masses appears to improve the management of MM patie nts by providing diagnostic material, samples for ancillary studies, and pr ognostic information. ST MM can be classified reliably into grades of progn ostic significance utilizing the classification of Bard et al. Intermediate -grade MM was the most frequent subtype present in ST masses. (C) 2001 Ame rican Cancer Society.