A 12 week old boy presented with a 6 cm heterogeneous solid mass with cystic change, involving the mid/lower pole of the right kidney. Grossly, the tumor was soft and hemorrhagic with cystic degeneration.

	C. Eric Freitag, M.D. Fellow, Surgical Pathology Mayo Clinic @CEFreitagMD
	Sounak Gupta, M.B.B.S., Ph.D. Consultant, Anatomic Pathology Mayo Clinic Assistant Professor of Pathology Mayo Clinic College of Medicine and Science

A 29 year old female presents with large, painless right abdominal wall mass. The mass was excised, and microscopic evaluation demonstrated an infiltrative spindle cell mesenchymal neoplasm with mild cellular atypia. Immunohistochemical stains showed the lesional cells to be positive for CD34 and S100, and negative for SOX-10, Melan A, HMB-45, cytokeratin AE1/AE3, tyrosinase, myogenin, MyoD1, KIT, ALK and STAT6.

	Sandra Gjorgova Gjeorgjievski, M.D. Fellow, Surgical Pathology Mayo Clinic @SGjorgova
	Karen Fritchie, M.D. Consultant, Anatomic Pathology Mayo Clinic Associate Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine and Science @KarenFritchieMD

A 7-year old boy presented with growing skin lesion on the back.

	Chady Meroueh, M.D. Fellow, Clinical Informatics Mayo Clinic
	Thomas Flotte, M.D. Consultant, Anatomic Pathology Mayo Clinic Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine and Science

64 year old female with an outside diagnosis of porphyria cutanea tarda (PCT), with a new onset of abdominal pain. She had a complex constellation of neurological symptomatology with unclear etiology. She is currently on Clonazepam, but over the past 2 months her spells have worsened. Analysis of porphyrins in urine (during an acute episode) and in feces, revealed several porphyrins elevated in an unusual pattern (Figure 1 and Figure 2 respectively). The erythrocyte porphobilinogen deaminase activity was normal.

	Ester Perales Clemente, Ph.D. Fellow, Clinical Biochemical Genetics Mayo Clinic
	Silvia Tortorelli, M.D., Ph.D. Consultant, Laboratory Genetics and Genomics Mayo Clinic Assistant Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine and Science