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.

Figure 1. Interface of the tumor and normal renal parenchyma is sharply demarcated.
Figure 2. The tumor is densely cellular with sheets and vague fascicles of plump spindle cells and focally hemangiopericytoma-like vessels are seen.
Figure 3. Immunohistochemistry for pan-trk with weak to moderate cytoplasmic and nuclear staining.
Figure 4. FISH for ETV6 using dual-color break-apart probe technique
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Photo of Cody (Eric) E. Freitag, M.D. C. Eric Freitag, M.D.
Fellow, Surgical Pathology
Mayo Clinic
@CEFreitagMD
Photo of Sounak Gupta, M.B.B.S., Ph.D. 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.

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Photo of Sandra Gjorgova-Gjeorgjievski, M.D. Sandra Gjorgova Gjeorgjievski, M.D.
Fellow, Surgical Pathology
Mayo Clinic
@SGjorgova
Photo of Karen Fritchie, M.D. 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.

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Photo of Chady Meroueh, M.D. Chady Meroueh, M.D.
Fellow, Clinical Informatics
Mayo Clinic
Photo of Thomas J. Flotte, M.D. 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.

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Photo of Ester Perales Clemente, Ph.D. Ester Perales Clemente, Ph.D.
Fellow, Clinical Biochemical Genetics
Mayo Clinic
Photo of Silvia Tortorelli, M.D., Ph.D. 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

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