Development and Validation of Ultra-Rapid Periodic Acid-Schiff Stain for Use in Identifying Fungus on Frozen Section.

CONTEXT.­: There is no standardized process for utilization of periodic acid-Schiff during intraoperative frozen sections to identify fungal organisms. OBJECTIVE.­: To develop a rapid staining process for fresh tissue with periodic acid-Schiff during intraoperative consultation and develop an appropriate control block. DESIGN.­: Muscle tissue was inoculated with 2 species of fungus (Aspergillus fumigatus and Paecilomyces spp) and grown at 3 different temperatures for 72 hours. Inoculated tissue was embedded in optimal cutting temperature compound, cut, and stained using a modified periodic acid-Schiff stain. The optimal control was determined for future use as the standard control. Multiple control slides were cut and stained, using successively shorter time intervals for each step. The staining process that provided accurate results in the shortest amount of time was deemed ultra-rapid periodic acid-Schiff. This method was validated by carryover studies and clinical specimens. RESULTS.­: Paecilomyces spp incubated at 30°C for 72 hours was the most optimal positive control, with numerous yeast and hyphal forms. The fastest staining process involved 2 minutes of periodic acid and Schiff reagent and 10 dips of light green solution. Tap water was as effective as distilled water. Validation was successfully achieved. Clinical cases all stained identical to formalin-fixed, paraffin-embedded tissue stained with hematoxylin-eosin and periodic acid-Schiff. CONCLUSIONS.­: Ultra-rapid periodic acid-Schiff provides fast and reliable identification of fungal organisms on fresh tissue. Development of a concurrent positive control allows for quality control and validation.

Fibrin-Associated Diffuse Large B Cell Lymphoma Found on Revision Arthroplasty of the Knee.

Fibrin-associated diffuse large B cell lymphoma (FA-DLBCL) is a rare Epstein-Barr viruspositive B cell lymphoma that is nonmass-forming, does not directly produce symptoms, and is incidentally discovered on histological examination of tissues excised for other reasons. Despite overlap in morphologic and immunophenotypic features with aggressive B cell neoplasms, FA-DLBCL shows an excellent clinical outcome, even with surgical excision alone. We report an extremely rare occurrence of FA-DLBCL found in association with a metallic implant on revision arthroplasty of the knee. This report also illustrates the need for an integrated multidisciplinary approach for accurate diagnosis and avoidance of overtreatment.

An unusual cause of bowel obstruction: Rhizopus Arrhizus diverticulitis.

Mucormycosis is a fungal infection primarily afflicting immunocompromised or diabetic patients. Its presentation ranges from rhino-orbito-cerebral infections to disseminated mucormycosis with angioinvasion. We present a patient who developed a bowel obstruction one month after bone marrow transplant and was diagnosed with Rhizopus arrhizus diverticulitis despite antifungal therapy since transplantation. She underwent surgical removal with immediate fungal resurgence, declined further invasive intervention and was discharged on palliative isavuconazole. Seven months later she is alive with fungal containment.

Treatment response with sirolimus for a pediatric patient with an EBV-associated smooth-muscle tumor after bone marrow transplantation.

Epstein-Barr virus-associated smooth-muscle tumors (EBV-SMTs) are unique and rare neoplasms described in immunocompromised patients. The case describes a nine-year-old female with a history of acute lymphoblastic leukemia with relapse and subsequent allogeneic bone marrow transplantation who presented with multiple EBV-SMTs of the liver. EBV utilizes the mammalian target of rapamycin (mTOR) pathway for tumor growth, and sirolimus, a mTOR inhibitor, has shown to result in a short-term response. We now report an extended treatment response with sirolimus in a pediatric patient with an EBV-SMT.