“Duodenal Submucosal Glandular Lesion with Brunner and Paneth Cell Differentiation”: A Variant of Pyloric Gland Adenoma? Morphologic and Immunohistochemical Similarities and Differences

Introduction/Objective

Duodenal epithelial polyps are reported in up to 3% of patients referred for upper endoscopy. Most include non-neoplastic lesions such as Brunner gland nodule/polyp and pancreatic or gastric heterotopia.

Neoplastic lesions such as pyloric gland adenomas (PGA) are less frequently encountered and have the propensity to progress to adenocarcinoma. Herein we report a duodenal submucosal glandular lesion that has a morphologic resemblance to PGA, but very different in several aspects. We compare and contrast the characteristics of these two lesions.

Methods

This was a 63-year-old man referred for an upper GI endoscopy for complaints of indigestion, dyspepsia, and weight fluctuation. Endoscopy showed a 13 mm polypoid lesion in the second portion of the duodenum, opposite to and separate from the ampulla. An en-bloc hot snare was used to resect the polyp. Histopathologic examination showed features reminiscent of PGA, namely a complex submucosal proliferation of tightly packed variably dilated glands and villous fronds lined by a monolayer of columnar cells with basally located round nuclei and prominent nucleoli. In contrast, however, the columnar cells in most of the lesion contained abundant mucinous cytoplasm resembling Brunner’s glands as well as areas of prominent paneth cell differentiation. The characteristic amphophilic ground glass cytoplasm of PGAs was only noted in a minor component of the lesion. MUC6 and MUC5AC, immunostains that are typically expressed in PGA, were negative. Additionally, p53 showed a wild-type pattern, beta- catenin showed normal membranous staining, and the Ki-67 index was low.

Results

After review of the literature and expert consultation, we were not able to fully classify this lesion under any documented entity, however, we believe that it could be akin to PGA. Authors hypothesized that PGAs may originate from stem cells within Brunner glands as a response to chronic injury. These cells may then differentiate upwards, forming gastric foveolar metaplasia or downwards giving rise to Brunner gland hyperplasia.

Conclusion

Based on this hypothesis, the proliferating cells are prone to mutations resulting in a hyperplasia/metaplasia to dysplasia sequence that leads to the formation of PGAs or lesions such as the one demonstrated here.

Abdominal Inflammatory Myofibroblastic Tumor: Minimal Inflammatory Infiltrate and Diffuse Immunoreactivity for Caldesmon are Potential Diagnostic Pitfalls

Introduction/Objective

Inflammatory myofibroblastic tumor (IMT) is an uncommon spindle cell lesion that can involve various organs and occurs in multiple body sites. While older terminology (i.e. inflammatory pseudotumor) suggested otherwise, recent molecular studies point toward a neoplastic pathogenesis for IMTs. Herein, we report a case of an abdominal IMT and discuss the morphologic and immunohistochemical pitfalls pertaining to this entity.

Methods

A 75-year-old woman presented with complaints of generalized abdominal pain and distention. An abdominal CT scan showed multiple peritoneal masses, the largest of which measured 23 cm. Biopsy revealed compact fascicles of bland spindle cells exhibiting diffuse actin and caldesmon immunoreactivity, consistent with a spindle cell tumor with smooth muscle differentiation. Mitotic activity was low-to-unapparent. Surgical excision was performed. The cut surface of the tumor was tan-white with hemorrhagic foci. Histopathologic examination of the tumor showed elongated spindle cells set in a loose myxoid stroma rich in blood vessels and a mixed inflammatory infiltrate. Deeper sections of the tumor were more cellular, showing a similar morphology to that seen in the original biopsy, which was virtually devoid of inflammatory cells. Immunohistochemistry showed diffuse staining for desmin, caldesmon, smooth muscle actin, and ALK. FISH analysis showed ALK gene rearrangement in 52% of tumor cells, confirming the diagnosis of IMT.

Results

Studies in the literature show that IMTs express smooth muscle markers such as SMA (90%) and desmin (50%). However, immunoreactivity for caldesmon is rarely reported. ALK immunoreactivity is seen in about 35–60% of cases, and when gene rearrangement involving ALK is detected the diagnosis can be confirmed.

Conclusion

Historically, several terms have been used to describe IMTs, including inflammatory pseudotumor and inflammatory pseudosarcomatous fibromyxoid tumor. While the nomenclature consistently implies an inflammatory infiltrate, this tumor could have various morphological patterns with some areas showing very little to absent inflammation, as demonstrated in our case. Hence, making an accurate diagnosis could be challenging on a limited biopsy. Therefore, ALK testing should be included as part of the diagnostic workup of spindle cell neoplasms with smooth muscle differentiation.

Epstein - Barr Virus (EBV) Associated B-Cell Lymphoma: An Unusual Involvement Of The Heart And Kidney In An HIV Positive Patient With Concurrent Cytomegalovirus (CMV) Pneumonia And Pneumocystis Jirovecii Pneumonia (PCP)

Introduction/Objective

We report a 68-year-old man with Human immunodeficiency virus (HIV) infection and significant weight loss during the past two years who presented with dyspnea. He was not receiving any treatment for HIV infection, and his viral load and CD4 count were 178000 copies/ml and 8 cells/mm3, respectively. The radiologic examination was concerning for Pneumocystis jirovecii pneumonia. The Bronchoalveolar lavage was positive for Pneumocystis jirovecii. The patient expired despite the comprehensive treatment, and the autopsy was requested.

Methods

The autopsy showed heavy lungs with diffuse consolidation and white discoloration involving all lobes. The left ventricular wall and right kidney cortex showed foci of white discoloration measuring 1 and 0.8 cm, respectively.

Results

The microscopic examination of lungs showed concurrent CMV pneumonia, and PCP confirmed by immunohistochemical staining for CMV and GMS special stain. The histologic evaluation of the heart and the right kidney and immunohistochemical staining for CD20 and CD3 in addition to in situ hybridization (ISH) for EBER revealed infiltrative malignant cells, which were positive for CD20 and EBER and negative for CD3. The EBV associated B-cell lymphoma involving the heart, and the right kidney was diagnosed

Conclusion

EBV is involved in human lymphomagenesis, particularly in HIV patients. There is a tendency for the lymphoma to involve the extranodal sites, including the CNS, gastrointestinal tract, liver, and bone marrow. However, the involvement of the heart and kidneys occurs very rarely. The autopsy findings of Lung co-infection with PCP and CMV and EBV associated lymphoma involving atypical locations is a rare and unique combination of AIDS-defining illnesses in this patient.