23-year-old male with an isolated soft tissue mass on the back measuring 1.5 cm.
The mass is centered in the dermis and extending into the underlying adipose tissue. It is well circumscribed, red dermal-based nodule.

Low power deep dermis centered tumor
Superficial nodular-boselated interface
Denser eosinophilic cytoplasm
Granular cytoplasm
Vacuolated cells
Capillary vessels
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Vishnu Serla, M.B.B.S.
Resident, Anatomic Pathology
Mayo Clinic
@vishnuserla
Jorge Torres-Mora, M.D.
Consultant, Anatomic Pathology
Mayo Clinic
Assistant Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science

A 39-year-old woman presents with a 6 cm recurrent polypoid mass situated in the left pharyngeal wall (piriform sinus), initially resected five years ago.

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Toshi Ghosh, M.D.
Fellow, Surgical Pathology
Mayo Clinic
@ToshiGhoshMD
Karen Fritchie, M.D.
Consultant, Anatomic Pathology
Mayo Clinic
Assistant Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science
@KarenFitchieMD

A 59-year-old kidney transplant patient presented after 1 week of low-grade fevers and non-productive cough. A CT scan of the lungs showed multiple mass-like lesions scattered bilaterally throughout, concerning for post-transplant lymphoproliferative disease or an infectious process. She underwent a bronchoalveolar lavage (BAL) with biopsy of a left upper lobe mass. Images of the Gram stain and modified acid-fast stain are shown in the figures below.

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Sarah Jung, Ph.D.
Fellow, Clinical Microbiology
Mayo Clinic
@JungASarah
Nancy Wengenack, Ph.D.
Consultant, Clinical Microbiology
Mayo Clinic
Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science
Courtney Klapperich, MLS(ASCP)
Education Specialist
Instructor in Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science

A 68-year-old male with history of chronic lymphocytic leukemia presented with subnephrotic range proteinuria (protein/creatinine ratio of 2.5), hemoglobin (13.1 g/dl) and ESR of 50 mm/hour. Core needle biopsy was performed to assess his proteinuria. Representative images of the biopsy are shown. Immunohistochemistry staining was performed and showed positive CD 20, CD 5, and CD 23.

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Mazen Osman, M.B., B.Ch.
Resident, Anatomic and Clinical Pathology
Mayo Clinic
Joseph Grande, M.D., Ph.D.
Consultant, Anatomic Pathology
Mayo Clinic
Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science

A 33-year-old female presents to her care team with liver cirrhosis (stage IV) and worsening liver failure. She is well known to her medical team and has a long history of blistering skin lesions in direct light. She received a liver transplant for her condition. The photomicrographs provided are of this patient’s explanted liver.

1) H&E low power magnification of explanted liver with cirrhotic nodules.

2) H&E low power magnification of liver parenchyma with coarse pigment deposition.

3) H&E high power magnification of liver parenchyma with coarse pigment depositon.

4) H&E high power magnification (polarized) of liver parenchyma with coarse pigment deposition.

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Elise Venable, M.B.B.S.
Resident, Anatomic and Clinical Pathology
Mayo Clinic
@VenableMBBS
Tsung-Teh Wu, M.D., Ph.D.
Consultant, Anatomic Pathology
Mayo Clinic
Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science

A 5 year old male patient with a complex phenotype was seen in clinic. He presented with developmental delay, feeding difficulty, cerebellar malformation, coagulation problems, hypothyroidism, retinitis pigmentosa, and bilateral hearing loss. Though not overweight, he also had abnormal distribution of body fat with fat pads in the lower back along with inverted nipples. Testing for congenital disorders of glycosylation (Figure1) showed results consistent with CDG Type I.
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Adam Guenzel, Ph.D. Resident, Laboratory Genetics and Genomics 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

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