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| Web: | mayocliniclabs.com |
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| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing | |
A 24-year-old patient just received a result of LSIL HPV 16+. The patient has a history of ASCUS HPV+ non-genotyped the year prior. The patient has no other pertinent medication history and does not wish to have children.
The correct answer is ...
1-year follow-up.
As you follow down the center of the diagram you will see first that the patient has a one-year follow-up for the ASCUS HPV+, then with the LSIL diagnosis has an additional year of follow-up regardless of the HPV status. Having progressive changes to cytology compounded by persistent HPV positivity and HPV 16 diagnosis can be concerning. However, the data shows that patients who are younger have a high chance of clearing HPV infections and cytologic changes.1,2
Additionally, guideline decision trees like the one in this case are immensely powerful tools in medicine. They distill data and knowledge into an easy-to-view format that non-medical patients can follow. They have been used in publications of these guidelines and others for years. They can also be distilled for informaticians, analysts, and engineers into clinical decision support logic for use in an EMR very easily by supplementing the branches into if/else logic functions. Some software has even utilized this format for knowledge, automation, and treatment recommendation (Epic and Trisotec).3,4,5
Jason Greenwood, M.D., M.S.
Fellow, Clinical Informatics
Mayo Clinic
Justin Juskewitch, M.D., Ph.D.
Senior Associate Consultant, Transfusion Medicine
Mayo Clinic
Assistant Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science
A 72-year-old man with recently diagnosed amyloidosis, AL (lambda)-type, based on mass spectrometric molecular typing and bone marrow involvement by 5%-9% clonal plasma cells (lambda-restricted), presented with gross hematuria, prompting a comprehensive bleeding diathesis laboratory evaluation. Findings included elevated von Willebrand factor (VWF) antigen (254%; reference range (RR) 55%-200%) with disproportionally decreased VWF latex immunoassay activity (75%; RR 55%-200%) and a VWF-activity/VWF-antigen ratio of 0.3. Factor X activity was also decreased (37%; RR 70%-150%), consistent with an amyloid-associated adsorptive coagulopathy.
The correct answer is ...
Low ADAMTS-13 antigen.
Prior testing confirmed persistent elevations of VWF antigen and decreased VWF activity, with a low VWF-activity/VWF-antigen ratio of less than 0.5. Further clinical investigations revealed cardiac and peripheral nervous system involvement, manifesting as orthostatic hypotension and peripheral neuropathies.
In one single-center prospective observational study that included 111 consecutively treated patients with a new diagnosis of AL-type amyloidosis, 76% of patients had elevated VWF antigen levels, possibly reflecting endothelial dysfunction. In a multivariate analysis, levels of NTproBNP (either ≥4000 or ≥8500 pg/mL) and low systolic blood pressure (SBP <100 mm Hg) were associated with worse survival.1 Notably, VWF antigen levels above 230% (U/dL) were also associated with a higher probability of early death and worse survival, independent of cardiac biomarker and low SBP.1,2 While low ADAMTS-13 levels correlated with high levels of NTproBNP, the ADAMTS-13 level had no independent prognostic significance.1
Additional points: Even if the VWF-activity and VWF-antigen levels are within the laboratory’s respective reference intervals, a decreased VWF-activity/ VWF-antigen ratio (especially if less than 0.5) should prompt further evaluation for congenital type 2A/2B/2M von Willebrand disease (VWD) or an acquired von Willebrand syndrome (AVWS). Subsequent analysis includes VWF multimer analysis, which, in our laboratory, is performed using high-resolution SDS gel electrophoresis followed by fluorochrome-conjugated antibody detection of VWF.3 A normal VWF multimer distribution from a healthy donor is shown in Figure A, top lane. Compared with the normal pattern, the patient’s sample displayed decreased abundance (intensity) of high and intermediate molecular weight multimers and increased abundance of low molecular weight multimers (Figure A, second lane). The classical triplet band pattern was altered with loss or absence of the central band and enhanced satellite bands, suggestive of enhanced VWF proteolysis (Figure B). A similar VWF multimer pattern was previously reported by Melnyk et. al. in a patient with AL-type amyloidosis (Figure A, lower two lanes, and B).4
Abdulrahman Saadalla, M.B., B.Ch.
Fellow, Special Coagulation
Mayo Clinic
Jansen Seheult, M.B., B.Ch., M.D.
Senior Associate Consultant, Hematopathology
Mayo Clinic
Assistant Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science
An 84-year-old-man with history of squamous cell carcinoma and Merkel cell carcinoma underwent neck dissection. One lymph node was found to be involved by chronic lymphocytic leukemia/small lymphocytic lymphoma (a), metastatic Merkel cell carcinoma (b), and metastatic basaloid squamous cell carcinoma colonized by Merkel cell carcinoma (c). The Merkel cell carcinoma cells are arranged in a nodular or nested pattern and have granular “salt and pepper” chromatin with indistinct nucleoli.
The correct answer is ...
It can be associated with an oncogenic virus.
Merkel cell carcinoma is an aggressive primary cutaneous neuroendocrine malignancy. The discovery of Merkel cell polyoma virus (MCV) has led to greater understanding of the pathogenesis of MCC. MCV was first described in 2008 (Feng, et al). In this study, the viral sequence identified in their lab was detected in 80% of the tested MCC tumors compared to 8% of control tissues from various body sites and 16% in control skin tissues. There is a smaller subset of cases that are not associated with this virus and appear to be driven by UV radiation exposure.
As demonstrated in this case, immunodeficiency such as concurrent CLL/SLL increases the risk of MCC development. Secondary malignancy is not uncommon in patients with MCC, with squamous cell carcinoma occurring most frequently.
MCC is typically positive for synaptophysin, chromogranin, and cytokeratin 20. CK20 will often show a paranuclear dot pattern. Small cell carcinoma of the lung may have similar morphology and is also typically positive for synaptophysin and chromogranin; however, cytokeratin 20 should be negative.
UV radiation exposure is a known risk factor for MCC. It frequently involves sun-exposed sites, such as the head and neck, and typically affects elderly, fair-skinned males.
Amanda J. Nguyen, M.D.
Resident, Anatomic and Clinical Pathology
Mayo Clinic
@AmandaJNguyenMD
Ruifeng (Ray) Guo, M.D., Ph.D.
Consultant, Anatomic Pathology
Mayo Clinic
Assistant Professor of Laboratory Medicine and Pathology
Assistant Professor of Dermatology
Mayo Clinic College of Medicine and Science
An 82-year-old man with a history of Type 2 diabetes and hypertension presents with episodes of nonbloody diarrhea and constipation. Imaging demonstrated severe sigmoid colitis with occlusion of the inferior mesenteric vein and tortuous collaterals. Colonoscopy was unremarkable except for segmental sigmoid colitis and an area of erythema in the rectum. Sigmoid colon biopsy showed colonic mucosa with congestion, focal Paneth cell metaplasia, erosion, possible arterialized capillaries, and reactive changes. After diagnosis, he underwent sigmoidectomy.
The correct answer is ...
Idiopathic myointimal hyperplasia of the mesenteric veins.
Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare noninflammatory type of chronic ischemic colitis of unknown etiology. Some have speculated the myointimal hyperplasia is a consequence of mechanical stress from a mesenteric arteriovenous malformation or arteriovenous shunting.1,2
IMHMV predominately affects adult males with nonspecific symptoms including abdominal pain, hematochezia, and diarrhea. IMHMV has a predilection for the left colon and rectosigmoid with features of ulceration, erythema, edema, and possibly strictures seen on colonoscopy.3,4
Microscopically, the pathognomonic feature of IMHMV in resection specimens is myointimal smooth muscle hyperplasia of the mural veins leading to stenosis or even complete occlusion, while the arteries are unaffected (Figure 2). An elastin stain such as Verhoff Van Gieson can be used to distinguish the mural veins from arteries (Figure 3). No lymphocytic phlebitis or lymphocytic cuff is identified in and around the mural veins. The overlying mucosa shows histologic changes consistent with ischemia including focal lamina propria hemorrhage, withered crypts, crypt architectural distortion, ulceration/erosion, and hyalinized lamina propria (Figure 1). Additionally, mucosal capillaries frequently display “arterialization,” subendothelial fibrin, and perivascular hyalinization likely due to venous hypertension (Figure 1). One study by Yantiss et al. mentions the mucosal capillary changes are sensitive and specific to assist in the diagnosis of IMHMV on mucosal biopsy.1,5
In many cases, patients with IMHMV are misdiagnosed with inflammatory bowel disease such as Crohn’s disease because of the similarities in presentation, endoscopy, and histology. IMHMV patients will fail medical therapy for inflammatory bowel disease and often undergo partial colectomy, which is curative. Recognizing histologic features of IMHMV is very important to prevent patients with IMHMV from being misdiagnosed with inflammatory bowel disease and receive unnecessary immunosuppressive treatment. The mucosal capillary changes can be a helpful finding on mucosal biopsy to make this distinction. In a resection specimen, the absence of transmural inflammation with the characteristic mural vein myointimal hyperplasia is pathognomonic of IMHMV. Thickening of the colonic wall on imaging also raises the clinical concern for neoplasia, which can be excluded with histologic evaluation. Another entity in the differential diagnosis with IMHMV is enterocolic lymphocytic phlebitis, which demonstrates lymphocytic phlebitis and/or a lymphocytic cuff, which are features not seen in IMHMV. Finally, radiation colitis can also enter the differential with IMHMV, but the absence of thin walled ectatic vessels and radiation induced stromal atypia can exclude this entity.5
Benjamin Van Treeck, M.D.
Fellow, Gastroenterology and Liver Pathology
Mayo Clinic
Roger Moreira, M.D.
Consultant, Anatomic Pathology
Mayo Clinic
Assistant Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science
A next-generation sequencing panel targeting genes associated with congenital neutropenia was ordered for a 2-month-old female infant with isolated persistent neutropenia. Two heterozygous pathogenic variants were identified in the SBDS gene (NM_016038.2): c.258+2T>C and c.183_184delinsCT. Representative reads are shown in Figure 1. Considering the presence of a highly homologous SBDSP1 pseudogene, long-range PCR using a SBDS-specific primer followed by Sanger sequencing were subsequently performed for variant confirmation (Figure 2).
The correct answer is ...
The SBDS variants are confirmed by Sanger sequencing and are in trans configuration. These findings therefore support a diagnosis of Schwachman-Diamond syndrome.
Schwachman-Diamond syndrome is an inherited bone marrow failure syndrome classically characterized by a triad of neutropenia, exocrine pancreatic insufficiency, and bony abnormalities. It is most often caused by biallelic pathogenic variants in the SBDS gene located at chromosome 7q11.21. The SBDS gene is involved in several processes such as ribosome biogenesis, mitotic spindle stabilization, DNA repair, and maintenance of stromal microenvironment.
Next-generation sequencing (NGS) approaches may be used, amongst others, for diagnostic investigation of suspected inherited bone marrow failure syndromes such as Schwachman-Diamond syndrome. In the presented case, NGS testing identified two pathogenic variants within the SBDS gene. While parental testing is often required to establish the phase of variants, in this case, visualization of the NGS reads demonstrated that the pathogenic variants identified are in trans configuration. Individual reads overlapping both variant loci and including the c.183_184delinsCT variant do not have the c.258+2T>C variant, and reads that include the c.258+2T>C variant do not have the c.183_184delinsCT variant. This finding indicates that the variants are in trans (on opposite alleles). (Figure 1).
The SBDS gene lies in close proximity with a highly homologous pseudogene SBDSP1. Variants leading to Schwachman-Diamond syndrome, such as those identified in this patient, most commonly arise from recombination or gene conversion events involving the SBDSP1 pseudogene. Gene conversion, which occurs in the setting of double-strand breaks, refers to a process in which genetic material is transferred from an initial DNA sequence and replaces a highly homologous receiver sequence, while leaving the initial sequence unchanged. Gene conversion events in which genetic material from a pseudogene replaces the sequence of a functional gene resulting in functional compromise of the receiver gene are involved in certain diseases such as Schwachman-Diamond syndrome.
From a diagnostic perspective, the highly homologous SBDSP1 pseudogene and gene conversion events raise diagnostic challenges related to ambiguous or erroneous alignment of NGS short reads with consequent risk for misdiagnosis. Accordingly, and as described in the case vignette, PCR amplification using SBDS-specific-primers which amplify the gene (and not the pseudogene) followed by Sanger sequencing of the amplicons may be used to confirm that identified variants lie within the SBDS gene and ensure accuracy of result interpretation. Figure 2 illustrates the electrophoregram of Sanger sequencing and provides confirmation that the variants are both present within the SBDS gene.
Therefore, these results support a diagnosis of Schwachman-Diamond syndrome, as the variants are in trans configuration and located in the SBDS gene.
Marie-France Gagnon, M.D.
Fellow, Laboratory Genetics and Genomics
Mayo Clinic
Ann Moyer, M.D., Ph.D.
Consultant, Laboratory Genetics and Genomics
Mayo Clinic
Associate Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science
@AnnMoyerMDPhD
A 67 year old man presented with several months of progressive fatigue, edema and diuretic resistant weight gain. About 6 months prior to developing these symptoms he had recovered from a COVID-19 infection that did not require hospitalization, and 3 months after that he received 2 doses of the Moderna COVID-19 vaccine. Upon presentation serum creatinine was elevated at 1.50 mg/dL (eGFR 46 mL/min/1.73m2). Urinalysis revealed markedly elevated protein (2779 mg/dl), 3-10 red blood cells, 4-10 WBCs, free fatty casts and oval fat bodies; a random albumin to creatinine ratio was above the assay analytical measuring range (>5565 mg/g). ANA was positive with a homogenous pattern and a titer of 1:640. Serum protein electrophoresis revealed a small monoclonal protein of 0.1g/dL, a decreased albumin and gamma-globulin fraction along with an increased alpha-2 globulin fraction suggestive of nephrotic syndrome. Bone marrow biopsy revealed no evidence of a plasma cell neoplasm. A diagnostic kidney biopsy revealed membranous nephropathy (MN, Figure 1). Phospholipase A2 receptor (PLA2R) immunostaining of the biopsy was negative (Figure 2), and serum anti PLA2R IFA and ELISA antibody tests were both negative.
The correct answer is ...
An antibody against an antigen other than PLA2R is responsible for the MN.
Membranous nephropathy (MN) is a glomerular disease which can occur at all ages and represents the most common cause of nephrotic syndrome in adults. In approximately 80% of cases there is no underlying cause (primary MN), whereas the remaining 20% occur in association with disorders such as systemic lupus erythematosus (SLE), hepatitis B, hepatitis C, or malignancy, or medications such as NSAIDS (1,2). MN appears to be caused by antibodies that target podocyte antigens resulting in antigen antibody complexes in the sub epithelial space of the glomerular basement membrane (GBM) (1,3).
Circulating antibodies directed towards M-type Phospholipase A2 receptor (PLA2R) can be detected in approximately 70% of adult patients with primary MN. Serum titers of anti-PLA2R antibodies can be used to both diagnose and monitor treatment response of patients with PLA2R-positive MN. A smaller percentage of MN cases (<5%) are associated with antibodies to thrombospondin type-1 domain-containing 7A (THSD7A). More recently, neural EGF-like-1 protein (NELL1) and exostosin 1/exostosin 2 (EXT1/EXT2) have been identified as a target antigens in MN (4,5). Interestingly, both were identified utilizing laser-capture microdissection and mass spectrometry to identify the target antigen in a series of PLA2R negative MN cases. The underlying target antigen for approximately 10% of MN remains to be identified. Although associated malignancy or autoimmune disorders have been identified for all forms of MN, malignancy appears more commonly associated with NELL1 positive MN, while autoimmune disorders appear more commonly associated with EXT1/EXT2 positive MN (5).
Antibodies targeting NELL1 appear to be the second most common cause of MN accounting for up to 23% of cases (4). On kidney biopsy NELL1-associated MN is characterized by incomplete capillary loop staining, IgG1 predominance, and is clinically associated with malignancy more often than other types of MN (2). NELL1-antigen antibody complexes within the kidney biopsy of this patient could be seen by immunohistochemistry (Figure 3) and electron microscopy (Figure 4). Work is ongoing to develop an assay to detect anti-NELL1 antibodies in serum.
Patrick Vanderboom, Ph.D.
Fellow, Clinical Chemistry
Mayo Clinic
John Lieske, M.D.
Consultant, Nephrology and Hypertension
Mayo Clinic
Professor of Medicine
Mayo Clinic College of Medicine and Science
