Chronic myopathy due to immunoglobulin light chain amyloidosis.

Amyloid myopathy associated with a plasma cell dyscrasia is a rare cause of muscle hypertrophy. It can be a challenging diagnosis, since pathological findings are often elusive. In addition, the mechanism by which immunoglobulin light-chain deposition stimulates muscle overgrowth remains poorly understood. We present a 53-year old female with a 10-year history of progressive generalized muscle overgrowth. Congo-red staining and immunohistochemistry revealed perivascular lambda light chain amyloid deposits, apparent only in a second muscle biopsy. The numbers of central nuclei and satellite cells were increased, suggesting enhanced muscle progenitor cell formation. Despite the chronicity of the light chain disease, the patient showed complete resolution of hematologic findings and significant improvement of her muscle symptoms following autologous bone marrow transplantation. This case highlights the importance of early diagnosis and therapy for this treatable cause of a chronic myopathy with muscle hypertrophy.

Utility of Intraoperative Frozen Sections during Thyroid Surgery.

Objective. To describe the usefulness of intraoperative frozen section in the diagnosis and treatment of thyroid nodules where fine needle aspirate biopsies have evidence of follicular neoplasm. Study Design. Retrospective case series. Methods. All patients have a fine needle aspirate biopsy, an intraoperative frozen section, and final pathology performed on a thyroid nodule after initiation of the Bethesda System for Reporting Thyroid Cytopathology in 2009 at a single tertiary referral center. Sensitivity, specificity, positive predictive value, and negative predictive value are calculated in order to determine added benefit of frozen section to original fine needle aspirate data. Results. The sensitivity and specificity of the frozen section were 76.9% and 67.9%, respectively, while for the fine needle aspirate were 53.8% and 74.1%, respectively. The positive and negative predictive values for the fine needle aspirates were 25% and 90.9%, respectively, while for the frozen sections were 27.8% and 94.8%, respectively. There were no changes in the operative course as a consequence of the frozen sections. Conclusion. Our data does not support the clinical usefulness of intraoperative frozen section when the fine needle aspirate yields a Bethesda Criteria diagnosis of follicular neoplasm, suspicious for follicular neoplasm, or suspicious for malignancy at our institution.