The novel form of amyloidosis derived from EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) preferentially affects the lower gastrointestinal tract of elderly femalesa.

AIMS: To characterise the clinicopathological features of amyloidosis due to EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1), a newly described amyloid type. METHODS AND RESULTS: We identified cases by searching the Mayo Clinic amyloid liquid chromatography and tandem mass spectrometry typing database for specimens with the universal amyloid signature proteins, abundant EFEMP1 spectra and absence of other specific amyloid precursor proteins. We also developed an immunohistochemical stain for EFEMP1 applicable to formalin-fixed tissue sections and performed electron microscopy in one case. We identified 33 specimens from 32 patients with EFEMP1 amyloid. Most patients were female (91%) with a mean age of 75 years, and most specimens (94%) were from the bowel. EFEMP1 amyloid was incidentally identified in specimens biopsied/resected for a variety of clinical indications. In bowel specimens, EFEMP1 amyloid involved blood vessels and interstitium of the lamina propria, submucosa and/or muscularis propria. Although the EFEMP1 deposits were weakly to moderately Congo red-positive with absent to weak birefringence, they were strongly positive for EFEMP1 by immunohistochemistry, had the characteristic fibrillar ultrastructure of amyloid and were readily identified by mass spectrometry. CONCLUSIONS: EFEMP1 amyloid is a recently described novel amyloid type that predominantly affects the bowel of elderly females. Because EFEMP1 amyloid is only weakly Congo red-positive, it may be overlooked without a high index of suspicion. However, its characteristic microanatomical distribution is highlighted by immunohistochemistry and its identity is readily confirmed by mass spectrometry. Based on its distinctive features, we propose that EFEMP1 amyloidosis be considered a new amyloid type.

Clinicopathological analysis of endometrial carcinomas harboring somatic POLE exonuclease domain mutations.

The Cancer Genome Atlas described four major genomic groups of endometrial carcinomas, including a POLE ultramutated subtype comprising ∼10% of endometrioid adenocarcinoma, characterized by POLE exonuclease domain mutations, ultrahigh somatic mutation rates, and favorable outcome. Our aim was to examine the morphological and clinicopathological features of ultramutated endometrial carcinomas harboring somatic POLE exonuclease domain mutations. Hematoxylin and eosin slides and pathology reports for 8/17 POLE-mutated endometrial carcinomas described in the Cancer Genome Atlas study were studied; for the remaining cases, virtual whole slide images publicly available at cBioPortal (www.cbioportal.org) were examined. A second cohort of eight POLE mutated endometrial carcinomas from University of Calgary was also studied. Median age was 55 years (range 33-87 years). Nineteen patients presented as stage I, 1 stage II, and 5 stage III. The majority of cases (24 of the 25) demonstrated defining morphological features of endometrioid differentiation. The studied cases were frequently high grade (60%) and rich in tumor-infiltrating lymphocytes and/or peri-tumoral lymphocytes (84%); many tumors showed morphological heterogeneity (52%) and ambiguity (16%). Foci demonstrating severe nuclear atypia led to concern for serous carcinoma in 28% of cases. At the molecular level, the majority of the Cancer Genome Atlas POLE-mutated tumors were microsatellite stable (65%), and TP53 mutations were present in 35% of cases. They also harbored mutations in PTEN (94%), FBXW7 (82%), ARID1A (76%), and PIK3CA (71%). All patients from both cohorts were alive without disease, and none of the patients developed recurrence at the time of follow-up (median 33 months; range 2-102 months). In conclusion, the recognition of ultramutated endometrial carcinomas with POLE exonuclease domain mutation is important given their favorable outcome. Our histopathological review revealed that these tumors are commonly high grade, have obvious lymphocytic infiltrates, and can show ambiguous morphology. As they frequently harbor TP53 mutations, it is important not to misclassify them as serous carcinoma.

Salivary gland amyloidosis: Proteomic identification and clinicopathologic characterization of 57 cases.

Salivary gland amyloidosis is an uncommon diagnosis. Most studies have focused on minor salivary gland biopsies as a surrogate site for diagnosing systemic amyloidosis, while only few studies have investigated major salivary gland amyloidosis. We retrospectively identified 57 major and minor salivary gland amyloidosis cases typed using a proteomics-based method between 2010 and 2022. Frequency of amyloid types, clinicopathologic features, and distribution patterns of amyloid deposits were assessed. The indication for salivary gland biopsy/resection (known in 34 cases) included suspected amyloidosis (N = 14; 41.2%), lesion/mass (N = 12; 35.3%), swelling/enlargement (N = 5; 14.7%), and rule out Sjogren syndrome (N = 3; 8.8%). Concurrent pathology was reported in 16 cases, and included chronic sialadenitis (N = 11), extranodal marginal zone lymphoma (N = 3), plasma cell neoplasm (N = 1), and pleomorphic adenoma (N = 1). We identified 3 types of amyloidosis: immunoglobulin light chain/AL (N = 47; 82.5%); immunoglobulin heavy chain/AH (N = 1; 1.8%), and transthyretin/ATTR (N = 9; 15.8%). The patterns of amyloid deposits (assessed in 35 cases) included: 1) Perivascular and/or periductal distribution (N = 18; 51.4%); 2) Mass formation (N = 9; 25.7%); 3) Stromal micronodule formation (N = 7; 20.0%); and 4) Diffuse interstitial involvement (N = 1; 2.9%). We also identified one case of AL amyloidosis localized to the major salivary gland, where only 6 other cases with adequate staging workup to exclude systemic amyloidosis were previously reported. In conclusion, salivary gland amyloidosis is an uncommon diagnosis but may be underrecognized due to low index of suspicion. Most cases of salivary gland amyloidosis are AL type, but a minority are ATTR. Therefore, proteomics-based typing remains essential for treatment and prognosis.

Bone marrow histopathology in POEMS syndrome: a distinctive combination of plasma cell, lymphoid, and myeloid findings in 87 patients.

POEMS is an uncommon syndromic disorder characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes. There are few descriptions of the bone marrow pathology of POEMS; therefore, peripheral blood smears and bone marrow aspirates and biopsies from 87 patients (143 total, 67 pretreatment, 76 posttreatment cases) with POEMS were studied. Plasma cell clonality was analyzed by flow cytometry, immunohistochemistry, and/or in situ hybridization. Monotypic plasma cells were detected in 44 pretreatment cases (66%); the majority of plasma cells expressed λ light chain (91%). The monotypic plasma cells typically were present in a background of increased polytypic plasma cells. Lymphoid aggregates were found in 33 (49%) pretreatment cases and in most cases were rimmed by plasma cells (97%). Megakaryocyte hyperplasia (36 cases) and clusters (62 cases) were frequent; however, none of the 43 cases tested had the JAK2(V617F) mutation. In summary, we have identified a novel constellation of features that should strongly suggest POEMS syndrome as part of the differential diagnosis. The constellation of λ-restricted monoclonal gammopathy, plasma cell rimming around lymphoid aggregates, and megakaryocytic hyperplasia in a bone marrow is highly suggestive of this diagnosis, especially in the context of a peripheral neuropathy.

Proteomic Identification and Clinicopathologic Characterization of Splenic Amyloidosis.

The spleen is a commonly encountered specimen in surgical pathology. However, little is known about the incidence, morphologic pattern, and clinical features of spleens involved by amyloidosis. We retrospectively identified 69 spleen amyloid cases typed using a proteomics-based method between 2008 and 2020. The frequency of amyloid types, clinicopathologic features, and distribution of amyloid deposits were assessed. Four amyloid types were detected: immunoglobulin light chain (AL) (N=30; 43.5%); leukocyte chemotactic factor 2 amyloidosis (ALECT2) (N=30; 43.5%); amyloid A (AA) (N=8; 11.6%); and fibrinogen alpha (AFib) (N=1; 1.4%). The splenic amyloid showed 5 distinct distribution patterns: (1) diffuse pattern, exhibited by most AL cases; (2) red pulp pattern, exhibited by most ALECT2 cases; (3) multinodular pattern, seen in subsets of AA and AL-kappa cases; (4) mass-forming pattern, seen in the AFib case; and (5) vascular only, seen in a subset of AA cases. Atraumatic splenic rupture was the most common reason for splenectomy in AL cases, while most ALECT2 spleens were removed incidentally during an unrelated abdominal surgery. Splenomegaly was significantly more common in AA spleens than in AL or ALECT2 spleens and was often the reason for splenectomy in this group. In conclusion, splenic amyloid may be underrecognized as it is often an incidental finding. Although, as expected, many of the spleens were involved by AL amyloidosis, ALECT2 emerged as another common spleen amyloid type. Although the spleen amyloid types exhibited characteristic distribution patterns, proteomics-based typing is warranted as some morphologic overlap still exists. Awareness of ALECT2 as a major spleen amyloid type is important for appropriate diagnostic workup and patient management.

Proteomic and Clinicopathologic Assessment of Penile Amyloidosis: A Single Institutional Review of 12 Cases.

OBJECTIVES: There is a paucity of data on penile amyloidosis. We aimed to assess the frequency of different amyloid types in surgical specimens from the penis involved by amyloidosis and correlate relevant clinicopathologic parameters with proteomic findings. METHODS: Since 2008, our reference laboratory has performed liquid chromatography/tandem mass spectrometry (LC-MS/MS) for amyloid typing. The institutional pathology archive and reference laboratory database were queried to retrospectively identify all penile surgical pathology specimens with LC-MS/MS results between January 1, 2008, and November 23, 2022. Archived H&E-stained and Congo red-stained sections were re-reviewed. RESULTS: Twelve cases of penile amyloidosis were identified, which represented 0.35% (n = 3,456) of penile surgical specimens. AL-type amyloid was most frequent (n = 7), followed by keratin-type amyloid (n = 3) and ATTR (transthyretin)-type amyloid (n = 2). AL-type amyloid cases often showed diffuse dermal/lamina propria deposition, whereas all keratin-type amyloid cases were localized to the superficial dermis. Two cases with keratin-type amyloid had concomitant cutaneous findings (penile intraepithelial neoplasia and condyloma). CONCLUSIONS: This series, the largest to date, demonstrates that penile amyloidosis has a heterogeneous proteomic landscape. To the best of our knowledge, this is the first study describing ATTR (transthyretin)-type penile amyloid.

Gastrointestinal amyloidosis: an often unexpected finding with systemic implications.

The gastrointestinal (GI) tract is a common site of amyloidosis, but the incidence, clinicopathologic features, and systemic implications of different types of GI amyloidosis are not well understood. GI amyloid specimens (N = 2511) typed using a proteomics-based method between 2008 and 2021 were identified. Clinical and morphologic features were reviewed in a subset of cases. Twelve amyloid types were identified, including AL (77.9%), ATTR (11.3%), AA (6.6%), AH (1.1%), AApoAIV (1.1%), AEFEMP1 (0.7%), ALys (0.4%), AApoAI (0.4%), ALECT2 (0.2%), Aß2M (0.1%), AGel (0.1%), and AFib (<0.1%). Amino acid abnormalities indicative of known amyloidogenic mutations were detected in 24.4% ATTR cases. AL, ATTR, and AA types all commonly involved submucosal vessels. They also showed some characteristic patterns of involvement of more superficial anatomic compartments, although there was significant overlap. Common indications for biopsy were diarrhea, GI bleed, abdominal pain, or weight loss. Amyloidosis was usually an unexpected finding, but most AL and ATTR patients were ultimately found to have cardiac involvement (83.5% of AL; 100% of ATTR). Although most GI amyloid is of AL type, over 10% are ATTR, over 5% are AA, and twelve different types were identified in total. GI amyloid is often unexpected but usually signals systemic amyloidosis, thus there should be a low threshold to perform biopsy with Congo red stain in patients with unexplained GI symptoms. Clinical and histologic features are nonspecific, and typing should be performed via a robust method such as proteomics as treatment hinges on correctly identifying the amyloid type.

Identification of amyloidosis of the urinary tract and prostate: Opportunities for early diagnosis & intervention in systemic disease.

OBJECTIVES: To determine the prevalence of different amyloid types and frequency of associated systemic amyloidosis in the urinary tract/prostate. METHODS: We studied Congo red-positive prostate (n = 150) and urinary tract (n = 767) specimens typed by a proteomics-based method between 2008 and 2020. Clinical follow up was available for a subset (urinary tract, n = 111; prostate, n = 17). Amyloid types were correlated with various clinicopathologic features. For patients with clinical follow up, chart review was performed to establish localized versus systemic disease, frequency of initial diagnosis of amyloidosis on urinary tract/prostate specimens, presence of cardiac disease, and death from disease-related complications. RESULTS: The most common amyloid types were AL/AH in urinary tract (479/767, 62 %) and localized ASem1 in prostate (64/150, 43 %). Urinary tract AL/AH amyloid was usually localized, but systemic AL amyloidosis occurred in both sites (urinary tract: 5/71, 7 %; prostate: 2/2, 100 %). ATTR amyloidosis was seen in over a third of cases (urinary tract: 286/767, 37 %; prostate: 55/150, 37 %). Urinary tract/prostate was the site of the initial ATTR amyloidosis diagnosis in 44/48 patients (92 %), and 38/48 (79 %) were subsequently found to have cardiac involvement. Seminal vesicle/ejaculatory duct involvement was pathognomonic for ASem1-type amyloidosis (39/39, 100 %). CONCLUSIONS: Over 40 % of patients had systemic amyloidosis, with urinary tract/prostate often the first site in which amyloid was identified. Since early recognition of systemic amyloidosis is critical for optimal patient outcomes, there should be a low threshold to perform Congo red stain. Proteomics-based amyloid typing is recommended since treatment depends on correctly identifying the amyloid type.

Amyloid deposition in an explanted bioprosthetic aortic valve: case report and review of the literature.

Herein we present a case of an 80-year-old gentleman who presented with exertional dyspnea status post aortic valve replacement with #23 Trifecta pericardial St. Jude aortic bioprosthetic valve (BV) 12 years prior. He subsequently underwent valve re-replacement due cusp calcification. Histologically, the surgically explanted BV revealed Congophilic deposits with birefringence under cross-polarized light. Extensive work-up identified no systemic source of amyloid in this patient. Liquid chromatography-tandem mass spectrometry-based (LC-MS/MS) proteomics showed the amyloid was composed of human-origin amyloid signature proteins (apolipoprotein A4, apolipoprotein E, serum amyloid P) and human-origin mu heavy chains. Background bovine collagen was also present. Transmission electron microscopy (TEM) showed collections of 7.5-10 nm nonbranching fibrils, consistent with amyloid. Using these techniques, we classified the amyloid as Mu heavy chain, deposition of which is highly unusual in BV. Finally, we provide a review of the literature regarding isolated amyloid deposition in BV.

Bone marrow amyloid: a comprehensive analysis of 1,469 samples, including amyloid type, clinical features, and morphologic distribution.

BACKGROUND: Bone marrow biopsy is common in patients suspected of having systemic AL amyloidosis. However, little is known about the incidence, morphology and clinical phenotype of non-AL amyloid types in bone marrow. METHODS: We retrospectively identified N = 1469 bone marrow amyloid biopsies typed using a proteomics-based method between 2008-2020. Frequency of amyloid types (N = 1469), distribution of amyloid deposits (N = 139), and clinical phenotypes (N = 355), with particular emphasis on cardiac involvement, were assessed. RESULTS: The amyloid types were: AL (N = 1172; 79.8%), ATTR (N = 240; 16.3%), AH (N = 38; 2.6%), AA (N = 17; 1.2%), and Aß2M (N = 2; 0.1%). Although there were characteristic morphologic features, including periosteal soft tissue and/or vascular involvement in ATTR, interstitial vascular involvement in AA, and variable anatomic compartment involvement in AL, none were pathognomonic. Most patients with both an M-spike and cardiac involvement had AL amyloid in their BM, but in over 10% the amyloid type was ATTR. Compared to AL patients, ATTR patients had higher stage cardiac amyloidosis and lower overall survival, which was mainly due to advanced cardiac stage. CONCLUSIONS: ATTR amyloid is common in bone marrow and its morphologic distribution overlaps with AL. Amyloid typing is critical as over 10% of patients with bone marrow amyloid, cardiac amyloidosis, and an M-spike have ATTR amyloidosis.

Amyloid Typing by Mass Spectrometry in Clinical Practice: a Comprehensive Review of 16,175 Samples.

OBJECTIVE: To map the occurrence of amyloid types in a large clinical cohort using mass spectrometry-based shotgun proteomics, an unbiased method that unambiguously identifies all amyloid types in a single assay. METHODS: A mass spectrometry-based shotgun proteomics assay was implemented in a central reference laboratory. We documented our experience of typing 16,175 amyloidosis specimens over an 11-year period from January 1, 2008, to December 31, 2018. RESULTS: We identified 21 established amyloid types, including AL (n=9542; 59.0%), ATTR (n=4600; 28.4%), ALECT2 (n=511; 3.2%), AA (n=463; 2.9%), AH (n=367; 2.3%), AIns (n=182; 1.2%), KRT5-14 (n=94; <1%), AFib (n=71; <1%), AApoAIV (n=57; <1%), AApoA1 (n=56; <1%), AANF (n=47; <1%), Aß2M (n=38; <1%), ASem1 (n=34; <1%), AGel (n=29; <1%), TGFB1 (n=29; <1%), ALys (n=15; <1%), AIAPP (n=13; <1%), AApoCII (n=11; <1%), APro (n=8; <1%), AEnf (n=6; <1%), and ACal (n=2; <1%). We developed the first comprehensive organ-by-type map showing the relative frequency of 21 amyloid types in 31 different organs, and the first type-by-organ map showing organ tropism of 18 rare types. Using a modified bioinformatics pipeline, we detected amino acid substitutions in cases of hereditary amyloidosis with 100% specificity. CONCLUSION: Amyloid typing by proteomics, which effectively recognizes all amyloid types in a single assay, optimally supports the diagnosis and treatment of amyloidosis patients in routine clinical practice.

Non-Hodgkin lymphoma presenting as acute pancreatitis: A rare occurrence.

Lymphoma often presents with extranodal manifestations. However, pancreatic involvement resulting in pancreatitis is rare. CD20-negative variants of diffuse large B-cell lymphoma are also rare and are more likely to present with extranodal involvement. Lymphoma should be considered in patients presenting with pancreatitis without traditional risk factors.

Divergent myoid, neuroendocrine, and perineural differentiation in a nasal tumor of a patient with Carney complex.

A 39-year-old woman with Carney complex presented with a stroke of undetermined etiology. Computed tomography showed bilateral thalamic infarctions and also an unsuspected multicompartmental cystic neoplasm that had eroded the anterior clivus and extended forward into the nasopharynx. Histologically, the mass appeared benign and was composed of spindle cells and multiple foci of striated muscle. Immunohistochemically, the spindle cells were strongly reactive for S-100 protein and to a lesser extent for CD57, collagen IV, neuron-specific enolase, smooth muscle actin, epithelial membrane antigen, and glut-1. The striated muscle cells were positive for desmin and myogenin. The MIB-1 labeling index was 0.5%. Ultrastructural examination was necessary to reveal the full extent of divergent differentiation. Ultrastructurally, the spindle cells showed divergent differentiation along several cell lines, including smooth muscle, neuroendocrine, hybrid smooth muscle-neuroendocrine, perineural-like cells, and striated muscle. The occurrence of this unique lesion in a patient with the Carney complex raises the possibility that it may be a rare component of the syndrome.

Epstein-Barr Virus-Positive Mucocutaneous Ulcer in an Immunosuppressed Patient.

Immunosuppressive medications, frequently used to treat inflammatory bowel disease, have been linked to the development of Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPD). We describe a case of an EBV-positive mucocutaneous ulcer involving the palate in an elderly woman with inactive Crohn's disease. This patient had been on high-dose azathioprine for a decade. Following diagnosis of her LPD and discontinuation of azathioprine, her oral ulcers resolved completely.

PD-1 Expression in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) and Large B-cell Richter Transformation (DLBCL-RT): A Characteristic Feature of DLBCL-RT and Potential Surrogate Marker for Clonal Relatedness.

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a low-grade B-cell neoplasm and ∼2% to 9% patients develop an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (Richter transformation, DLBCL-RT). Programmed death-1 (PD-1) pathway plays a crucial role in tumor host immunity evasion and its blockade has emerged as an effective anti-cancer immunotherapy. PD-L1 and PD-1 expression has shown predictive value in anti-PD cancer immunotherapy; however, it has not been well documented in CLL/SLL and DLBCL-RT. We evaluated PD-1 and PD-L1 expression by immunohistochemistry in 39 CLL/SLL, 15 DLBCL-RT, and 26 other DLBCL. In CLL/SLL, neoplastic B-cell PD-1 expression was weak and restricted to prolymphocytes/paraimmunoblasts within proliferation centers (PCs) and accentuated PCs of all sizes. Neoplastic B-cell PD-1 expression was highly prevalent and demonstrated increased intensity in DLBCL-RT, but in contrast was only rarely seen in other DLBCL (12/15 vs. 1/26; P<0.0001). An excellent correlation (90% concordance) was observed between neoplastic B-cell PD-1 immunohistochemistry positivity and molecularly defined CLL/SLL clonal relatedness in DLBCL-RT. PD-L1 expression was observed on the neoplastic B cells in rare DLBCL-RT and other DLBCL cases (1/15 vs. 1/26; P>0.05) as well as background histiocytes and dendritic cells. Overall survival of DLBCL-RT was significantly inferior to that of the other DLBCL (median, 16.9 vs. 106.1 mo; P=0.002). Our findings suggest a biological continuum from prolymphocytes/paraimmunoblasts in CLL/SLL PCs to the neoplastic B-cells in DLBCL-RT. The characteristic PD-1 expression in DLBCL-RT makes it a potential surrogate marker for determining clonal relatedness to CLL/SLL, which may have important prognostic and therapeutic implications.