A 25-year-old woman presented to the emergency room with three weeks' history of cough, a fever, and left-sided chest pain. She failed outpatient oral antibiotics and denied any renal manifestations. Her physical examination revealed no skin rash or joint problem. She had a past medical history of two episodes of pneumonia. She also denied smoking, alcohol use, and illegal substances abuse. Wedge biopsy was obtained.

	Osamah (Sam) Al Badri, M.B., Ch.B. Resident, Anatomic and Clinical Pathology Mayo Clinic
	Maxwell Smith, M.D. Consultant, Anatomic Pathology Mayo Clinic Assistant Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine

A 46-year-old female presents with episodes of nausea. Endoscopy shows a 3 cm submucosal mass in the stomach. The tumor cells are predominantly oncocytic, with abundant vaguely granular eosinophilic cytoplasm, tumor necrosis, and invasion into the subserosal connective tissue. Focally, the tumor demonstrates higher-grade primitive areas. Immunohistochemistry shows that the tumor cells are positive for S100 and SOX10, while negative for keratin, synaptophysin, chromogranin, desmin, MelanA, DOG1, and CD117. Genetic studies confirm an EWSR1-ATF1 fusion.

	Daniel (Dan) P. Larson, M.D. Resident, Anatomic and Clinical Pathology Mayo Clinic
	Jennifer Boland Froemming, M.D. Consultant, Anatomic Pathology Mayo Clinic Associate Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine

A 71-year-old female presented with recent onset severe epistaxis and generalized ecchymoses, without antecedent trauma over the prior 2 to 3 weeks. For the severe epistaxis, she required nasal packing and received a platelet transfusion. She had no prior history of bruising or bleeding. Laboratory results: Hb 12.3 g/dL, Platelet count 245 x 10⁹ /L, PT 9.2s (RR: 8.4-12s), INR 0.9, APTT 27s (RR:21-33s), Thrombin time 19s (RR: 16-25s), PFA Collagen-Epi >265s (RR 70-165s), PFA Collagen-ADP 152s (RR 50-115s), Factor VIII activity 174% (RR 55-205%), VWF Antigen 170% (RR 55-200%), Ristocetin Cofactor 192% (RR 55-200%), and normal Factor XIII qualitative assay. Her platelet aggregation studies were as follows:

	Jose Jara Aguirre, M.D. Resident, Anatomic and Clinical Pathology Mayo Clinic
	Aneel Ashrani, M.D. Consultant, Hematology Mayo Clinic Assistant Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine

A 40-year-old female presented with abdominal pain and diarrhea. Abdominal CT scan showed significant wall thickening of cecum.  Right hemicolectomy was performed.  Histologic sections revealed an extensive atypical lymphoid infiltrate involving the full thickness of the cecal wall. It is composed of a diffuse to vaguely nodular proliferation of intermediate to large atypical lymphoid cells with round to slightly irregular nuclear contours, coarse chromatin, and moderate to ample pale cytoplasm. Some of the cells have a slightly plasmacytoid appearance. The tumor cells are positive for CD20, BCL6 (90%), and IRF4/MUM1 (90%), are suspicious for being kappa light chain restricted, have an elevated proliferation index per Ki-67 staining (90%), and are negative for CD3, CD5, CD10, CD21, CD23, CD138,  BCL2, cyclinD1 and MYC. No underlying CD21 or CD23-positive follicular dendritic cell meshworks are appreciated.  Interphase FISH studies demonstrated rearrangement of BCL6 and IRF4 but not of BCL2 or MYC.

	Hee Eun Lee, M.D., Ph.D Resident, Anatomic and Clinical Pathology Mayo Clinic
	Ellen McPhail, M.D. Consultant, Hematopathology Mayo Clinic Associate Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine