bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mesonephric-Like Adenocarcinoma: Two Cases Of A Rare Entity And Review Of Literature
Authors: Liu Y , Karnezis A 
Published: October 2020

Abstract

Introduction/Objective
Mesonephric-like adenocarcinoma (MLA) is a rare gynecologic malignancy occurring in the uterus and ovary and is morphologic similar to cervical mesonephric adenocarcinoma. We present two cases of mesonephric-like adenocarcinoma of the ovary.

Methods
The first case is a 72-year-old female presented with abdominal pain with bloating. Abdominal CT scan showed a 7.4 x 6.3 x 6.1 cm heterogenous right adnexal mass. The second case is a 66-year-old female with history of heavy bleeding and endometriosis, status post total abdominal hysterectomy with bilateral salpingo-oophorectomy 20 years ago. Abdominal CT scan demonstrated a 5.3 cm right pelvic mass and 12.5 cm right pelvic sidewall lymph node.

Results
Both tumors have characteristic variety of features including ductal, tubular, retiform, papillary, solid and infiltrative morphological patterns. Cytologic atypia is mild to moderate. The histological features can raise a broad differential diagnosis including primary tubo-ovarian carcinomas, sex cord-stromal tumors, and metastatic carcinomas. Immunohistochemical stains demonstrate the ovarian tumor cells are positive for multiple pan-epithelial markers (AE1/AE3); negative for sex cord-stromal markers (inhibin and calretinin); positive for PAX8, GATA3, TTF1, and CD10; and negative for ER, PR, and WT1. In the first case, a small incidental endometrial carcinoma arising from an endometrial polyp was also identified. Morphologically, it is distinct from the ovarian mesonephric-like adenocarcinoma.

Conclusion
Morphological and immunohistochemical features of the two tumors are consistent with MLA, a very rare ovarian tumor that is thought to arise either from mesonephric remnants in the para-ovarian tissue or by trans- differentiation from a benign or neoplastic Mullerian precursor. These tumors are reported to have a very high frequency of KRAS mutations followed by PIK3CA mutations. Due to their rarity, the clinical behavior of these tumors is unknown.
Examination Of Nail Clippings For Onychomycosis: Histologic Observations With Microbiologic Correlations
Authors: Liaquat S , Bryson A , Mochel M 
Published: October 2020

Abstract

Introduction/Objective
Appropriate management of onychomycosis, the most common disease of the nail unit, depends on accurate and timely diagnosis. Histologic evaluation of nail clippings, paired with histochemical techniques such as Periodic acid-Schiff (PAS), is a rapid, sensitive method for diagnosis of onychomycosis. While studies have compared testing modalities for onychomycosis, few have systematically evaluated histologic changes of the nail plate and correlated findings with concomitant microbiologic culture.

Methods
A consecutive series of nail clipping specimens between July 2016 to July 2019 from our institution were evaluated. Clinical data were collected, H&E and PAS stains were examined for histologic nail plate alterations and fungal presence, morphology, location, and abundance. Concurrent culture results were also collected and correlated.

Results
Histologic slides, including PAS, of nail clippings were evaluated from 131 patients (median age 57, 65% female). 53 cases (40%) were positive for fungal organisms by PAS stain: 26 cases showed diffuse fungal involvement, while 27 cases showed focal fungal involvement, limited to one 200x field. Of the PAS-positive cases, 47 cases showed predominantly hyphae and 6 cases showing predominantly yeast-like morphology. Nail plate histologic changes associated with PAS positivity included parakeratosis (p= 0.0071) and neutrophilic aggregates (p=0.0017).
Of the total cases evaluated by histology, 67 cases had concomitant cultures performed, with 17 of these cases (25%) positive for fungal growth. Of the 23 PAS-positive cases with simultaneous culture sent, only 9 cases (39%) were positive for fungal growth. Conversely, of the 44 PAS-negative cases with simultaneous culture sent, 8 cases (18%) were positive for fungal growth. For cases positive by both PAS and fungal culture, significant correlations between fungal morphology on PAS and microbiologic speciation were not observed.

Conclusion
While PAS stains appear overall more sensitive for onychomycosis, both PAS and culture methods are falsely negative in a significant number of cases. In cases of high clinical suspicion for onychomycosis, consideration of employing more than one testing modality is recommended. Of note, histologic examination may reveal nail plate changes associated with fungal infestation, including nail plate parakeratosis and neutrophilic aggregates.
PD-L1 Expression in Sarcomas: An Immunohistochemical Study
Authors: Cunningham C , Schnabel J , Esebua M , Layfield L 
Published: October 2020

Abstract

Introduction/Objective
Immunotherapy is increasingly used for the treatment of metastatic melanoma and carcinomas. PD-I (programmed death 1) and its associated ligand (PD-L1) inhibits the activation of T lymphocytes. This inhibition can be impacted by a number of drugs. Response to these drugs is predicted by assessment of PD-L1 expression. PD-L1 expression varies between 19% and 92% in melanomas and carcinomas. PD-L1 expression is less well documented for sarcomas.

Methods
Fifty-one sarcomas of various histopathologic types were immunohistochemically stained (IHC) for PD-L1 using the antibody clone SP263 (Ventana, Tuscan, AZ). Membrane staining of tumor cells was quantitated as a percentage of total tumor cells. Sarcomas were judged as non-expressors (less than 1%) low-expressors (1 to 50%) and high expressors (greater than 50%). The percentage of each type of sarcoma judged as an expressor was determined.

Results
The percentage of each type of sarcoma expressing PD-L1 is reported and 20% of sarcomas expressed PD- L1. The percentage of sarcomas expressing PD-L1 varied significantly between types but the majority of sarcomas were non-expressors.

Conclusion
PD-L1 IHC expression is valuable in predicting response to immune-modulating drugs. Such therapies may be useful for treatment of metastatic sarcomas. Expression of PD-L1 in carcinomas and melanomas is variable ranging from 19% to 92%. In our study, a minority (20%) of sarcomas expressed PD-L1. Other studies have shown similar results with between 1.4 and 59% (average 24%) of sarcomas expressing PD-L1. Expression appears to be type specific. These finding suggest that PD-L1 based therapy may be less useful in sarcomas than in other malignancies.
Gastric Carcinoma with Lymphoid Stroma: A Rare Case Report with EBV Negativity
Authors: Alqassim E , Taherian M , Huang Y 
Published: October 2020

Abstract

Introduction/Objective
Gastric carcinoma with lymphoid stroma (GCLS) is a distinct and rare histologic subtype of gastric adenocarcinoma that is characterized by undifferentiated carcinoma mixed with prominent lymphoid cell infiltration. Around 80% of GCLS cases are associated with Epstein-Barr virus (EBV) infection. Here we report a case of EBV-negative GCLS.

Methods
The patient was a 79-year-old female with a recent history of abdominal distention, weight loss, and gastrointestinal bleeding who presented for evaluation. Endoscopy found a 4.6 mm lobulated lesion at the incisura of the stomach with endosonographic evidence of invasion through the submucosa. Biopsy was consistent with intramucosal diffuse neoplasm, favoring adenocarcinoma. The decision was made to do subtotal gastrectomy.

Results
The patient underwent distal gastrectomy with Billroth 2 reconstruction. Gross examination of the stomach revealed a firm 1.4 cm nodule in the background of diffuse mucosal granularity in the adjacent stomach.
Microscopically, the tumor invaded the submucosa without lymph nodes involvement.
Staining showed the tumor diffusely positive for CAM5.2, focally and weakly positive for pancytokeratin and CK7, while negative for CK20. Mismatch repair (MMR) proteins staining demonstrated a loss of nuclear expression of MLH1 and PMS2. Her2/Neu FISH was non-amplified. The tumor was found to be EBV negative by EBER ISH while PD-L1 was expressed. The histopathological findings confirmed the final diagnosis of gastric carcinoma with lymphoid stroma (GCLS).

Conclusion
We report a case of GCLS that was EBV negative with non-amplified HER2, while MMR-deficient, and PD-L1 positive. These results suggest that this tumor subtype may be less responsive to targeted therapy, but show susceptibility to immune checkpoint inhibitors.
Segmental Diffuse Inflammatory Pseudopolyps Associated With Diverticulitis
Authors: Aghighi M , Rashidbaigi A , Kang Y 
Published: October 2020

Abstract

Introduction/Objective
Inflammatory pseudopolyps (IPs) often develop in response to chronic active inflammation in patients with inflammatory bowel disease (IBD). IPs can be diffuse and numerous in severe IBD. IPs can also occur from other chronic active injuries, such as ulcers, persistent infection, ischemic colitis, anastomotic site and diverticulitis. IPs arising from diverticulitis is uncommon and generally few in numbers.
We report a rare case of a patient with segmental diffuse IPs associated with diverticulitis in the absence of IBD.

Methods
A 59-year-old male patient with a history of sigmoid diverticulitis presented with abdominal pain and was treated with antibiotics. Three months later he had severe recurrent diverticulitis. CT scan showed wall thickening of the sigmoid colon and multiple sigmoid diverticula. Colonoscopy showed extremely severe inflammatory colitis in the area of diverticulitis between 25.0 and 35.0 cm from the anal verge. Biopsies revealed cryptitis, crypt abscesses, crypt architecture distortion and Paneth cell metaplasia. The patient underwent laparoscopic left colectomy.

Results
The rectosigmoid colon specimen is 18.0 cm in length and 6.0 cm in diameter. There was a 7.5 cm segment with numerous polyps. Multiple diverticula with diverticulitis were also identified in this region. The rest of the colon was unremarkable. Microscopic examination revealed numerous IPs and multiple diverticulitis. No evidence of IBD was identified.

Conclusion
To our knowledge, this is the first time that segmental and diffuse IPs are described with associated diverticulitis in the absence of IBD. The pathogenesis of IPs in non-inflammatory bowel disease is not well described. Previously, it was reported that diverticulosis and subsequent diverticulitis has no significant impact on the development of IPs, and IPs may arise independent of location and time of diverticulitis. Sporadic IPs may also appear without any underlying pathology. In the current case, there were multiple diverticula and diffuse diverticulitis, which may have contributed to the diffuse IPs. Further clinical inquiries revealed no clinical signs and symptoms of IBD.
Hepatoblastoma With Rubinstein-Taybi Syndrome: A Rare Association
Authors: Arshi J , Allison D , Rao D 
Published: October 2020

Abstract

Introduction/Objective
Hepatoblastoma is a malignant neoplasm of liver, exclusively seen in pediatric population. It has been known to occur with various syndromes like Li-fraumeni, Beckwith-Wiedemann, and Simpson-Golabi- Behmel among others. Small undifferentiated cells and macro-trabecular pattern with increased mitotic activity and AFP&gt;100 are associated with unfavorable prognosis. Rubinstein-Taybi syndrome is a rare genetic disease. Even though there has been intensive research on the genetic and epigenetic function of the CREBBP and EP300 genes in animal models, the etiology of this rare and devastating syndrome is largely unknown. Hepatoblastoma with Rubinstein-Taybi syndrome is an extremely rare occurrence.

Methods
Here we present an incidental case of Hepatoblastoma with Rubinstein-Taybi syndrome

Results
A 17-month-old Caucasian female with Rubinstein-Taybi syndrome, was found to have an incidental 1.1 cm nodule in the right lobe of liver. Her AFP was elevated (244.9ng/ml). Hepatic resection revealed a well-circumscribed tan white mass, measuring 3.5 cm in the greatest dimension. On microscopy, uniform round to cuboidal cells resembling fetal hepatocytes, with finely granular cytoplasm, small round nuclei, and indistinct nucleoli were seen. The cells were arranged in solid sheets and scant trabecular arrangement separated by narrow sinusoids. The tumor displayed predominantly fetal histology, with rare embryonal and small undifferentiated cell nests. The diagnosis of Hepatoblastoma was made. The patient underwent chemotherapy and was doing well at 5-years follow-up.

Conclusion
Extensive screening of patients in recent times has revealed mutations in CREBBP and EP300 in only around 50% of cases. The genetic and epigenetic associations of the syndrome in the remaining half of cases remains to be identified. Hepatoblastoma with Rubinstein-Taybi Syndrome is an extremely rare occurrence and might shed some light on other genes that could be involved in this syndrome. Further studies to review the mutation spectrum to understand the causative molecular mechanisms are deemed essential.
Unusual Case of Multiple Synchronous Gastrointestinal Stromal Tumors of the Jejunum Presenting as an Arteriovenous Malformation
Authors: Murzabdillaeva A , Taha H , Hausner R J 
Published: October 2020

Abstract

Introduction/Objective
Gastrointestinal stromal tumor (GIST) arises from the interstitial cell of Cajal. 30% of GISTs arise in the jejunum. GISTS are generally solitary although multiple GISTs may be synchronous or metachronous. There are a few reports of a GIST of the jejunum mimicking a vascular malformation/arteriovenous malformation (AVM) prior to surgical excision.

Methods
Herein, we report a case of four synchronous GISTs of jejunum. One GIST, highly vascularized, presented with lower gastrointestinal bleeding. The patient was a 40-year-old female presenting with epigastric pain and melena.

Results
She was found to have an ulcerated lesion in the distal jejunum by capsule enteroscopy and double balloon enteroscopy, interpreted as an arteriovenous malformation and tattooed. Several other non-ulcerated “polyps” were described. Gross examination of the ensuing segmental resection of jejunum demonstrated four bosselated tumors ranging from 3.1 cm to 6.5 cm. Microscopically, three tumors did not extend to the surface of the jejunum and were predominantly composed of spindle cells. One tumor (identified by tattoo) extended to the surface with ulceration. This tumor was dominated by wide vascular channels with a spindle cell component between the channels. The four tumors were each positive for CD117, DOG1, and Succinate dehydrogenase B (SDH), identifying the four tumors as non-SDH-deficient GISTs. Ki-67 proliferation index was less than 5% in all four masses.

Conclusion
Multiple GISTs are rare, classified as either sporadic or familial. Familial GEISTs are described in neurofibromatosis type 1, Carney’s triad and Carney-Stratakis syndrome. Pediatric GISTs, with clinical and genetic features often differing from typical adult tumors may also be multiple. Our patient’s four GISTs are considered multiple synchronous sporadic neoplasms. This case serves as an important reminder for pathologists consider GIST in the evaluation of a highly vascular gastrointestinal proliferation and keep in mind the possibility of multiplicity.
Case Report: Malakoplakia Developing in the Graft Colon Post Intestinal Transplant
Authors: Dimopoulos Y , Zeck J , Kallakury B 
Published: October 2020

Abstract

Casestudy
Malakoplakia is a rare chronic granulomatous disease thought to be caused by a macrophage bactericidal defect and most commonly affecting the genitourinary tract. Most cases are associated with chronic infections or immunosuppression, with most transplant related cases observed after renal transplantation.

Results
A male in his thirties developed short gut syndrome secondary to injuries and subsequently underwent a small and large bowel transplant and was treated with immunosuppressive medications.
He developed multiple episodes of acute rejection and multiple infectious foci, including a peri-rectal fluid accumulation growing Escherichia Coli, bacteremia with Klebisella oxytica, and Epstein Barr Virus viremia. Functional imaging revealed increased activity in mesenteric lymph nodes and in the peri-rectal fluid accumulation. On endoscopy, a rectal ulcer associated with mucosal protuberance was noted and tissue was obtained for pathologic diagnosis.
Histologic examination revealed mucosal infiltration by numerous macrophages with abundant granular cytoplasm. Michaelis-Gutmann bodies (considered pathognomonic for malakoplakia) were identified showing PAS and Von- Kossa positivity. Acid fast stain was negative. These findings supported the diagnosis of malakoplakia.
Other differential diagnoses were considered, including post-transplant lymphoproliferative disorder, neoplasia, infection with mycobacterial or fungal species, and secondary hemophagocytic lymphohistiocytosis syndrome. These were excluded based on the characteristic histologic findings.
Given the diagnosis, treatment with oral antibiotics was attempted. Follow up biopsies revealed disease persistence and the patient was transitioned to a prolonged course of intravenous antibiotics and bethanechol, with eventual histologic response. Unfortunately, due to stenosis and adhesions that developed secondary to the episodes of acute rejection, the patient eventually underwent graft explanation.

Conclusion
Our case highlights the risk factor milieu encountered in intestinal transplant patients and the prolonged treatment often required to treat malakoplakia. Additionally, malakoplakia constitutes an unusual consideration in intestinal transplant patients and prompt diagnosis is required to direct proper management of these patients.
Checkpoint Inhibitor-Induced Colitis: A Case Series
Authors: Avalos Hernandez S R , Anderson S A , Dal Zotto V 
Published: October 2020

Abstract

Introduction/Objective
Checkpoint inhibitors are novel immune-stimulating antibodies that have revolutionized the management and prognosis of several malignancies. The primary targets are cytotoxic T-lymphocyte–associated antigen-4 (anti-CTLA-4; e.g. pembrolizumab) and programmed cell death-1 receptor (anti-PD-1; e.g. ipilimumab and nivolumab). In spite of the significant advantages, many immune-related adverse effects have been identified. One of which is checkpoint inhibitor-induced colitis (CIC). Although there is awareness of the histopathologic features of anti- CTLA-4 induced colitis, there is much to be discovered about the pathologic features of anti-PD-1 colitis.

Methods
We herein report three cases of CIC. There were two women and 1 male (age range, 50 to 73-years-old, mean 64-years-old) who presented with diarrhea and/or hematochezia after multiple cycles of pembrolizumab or ipilimumab/ nivolumab combination therapy. Endoscopic examination was abnormal in all of these cases.

Results
The histologic features were similar in two cases, with moderate active chronic colitis and one case with focal active colitis. Two of the three patient were given steroids in addition to their regular medications with symptom improvement. One patient was removed off all medications and enrolled into hospice due to disease progression. CIC has been an increasingly recognized immune-related adverse effect that has a wide spectrum of clinical presentations ranging from mild diarrhea and abdominal pain to severe colitis and intestinal perforation. However, it is thought to be underestimated. Histologically, CIC can mimic inflammatory bowel disease, microscopic colitis and active colitis. Our cases showed histopathologic features mimicking those of ulcerative colitis.

Conclusion
Awareness of CIC is crucial for the multidisciplinary management essential for these patients. The histopathologic pattern coupled with the clinical history can allow pathologists to confirm the diagnosis of CIC and facilitate timely diagnosis and treatment.
Collision Tumor of the Kidney with Clear Cell Renal Cell Carcinoma and Papillary Renal Cell Carcinoma Components: Report of a Rare Case
Authors: Avalos Hernandez S R , Liu S , Sameeta F , Mneimneh W 
Published: October 2020

Abstract

Introduction/Objective
Collision tumors refer to the phenomenon where distinct, well-defined tumor subtypes are present within a single lesion. While this phenomenon has been described in different organs, it has been rarely encountered in renal tumors outside the context of rare tumor susceptibility syndromes. Collision tumors of the kidney may encompass any known benign or malignant renal tumor types. However, a collision tumor of two different renal cell carcinoma (RCC) subtypes is remarkably rare.

Methods
A 43-year-old male was referred to our institution for the management of a right lower pole renal mass. The right radical nephrectomy specimen revealed a 6.5 x 5.0 x 4.0 cm well circumscribed, yellow-orange and hemorrhagic cortical mass abutting the renal capsule and extending into the renal sinus fat. A grossly distinct 1.5 x 1.4 x 1.2 cm pale, nodular area was demonstrated at the periphery of the tumor.

Results
Microscopically, the tumor displayed two distinct, neoplastic components within the same mass, without transitional morphology. The majority of the tumor consisted of a nuclear-grade-2 conventional clear cell RCC, while the peripheral nodule represented a type-2 papillary RCC component. Immunostains further supported these findings: The papillary component was strongly and diffusely positive for CK7 and P504S/AMACR with variable EMA and vimentin expression, and negative for CAIX, while the clear cell component was positive for CAIX, EMA and vimentin with only focal and weak staining for CK7 and faint nonspecific P5O4S/AMACR staining. TFE3 Mart1 and HMB45 immunostains were negative in the tumor.

Conclusion
Collision tumor of the kidney with two distinct RCC subtypes is an exceedingly rare finding. Careful gross examination may be the first clue to identify such lesions, and sampling of all grossly distinct tumor areas is crucial.
The identification of collision tumors may have important therapeutic implications, given the difference in pathophysiology and outcome between RCC subtypes.