Hyalinizing clear cell carcinoma of the salivary gland is a rare neoplasm, accounting for only less than 1% of malignancies arising from the salivary gland. It is molecularly defined by the expression of the EWSR-ATF1 fusion oncogene. To date, there has been no previous studies published yet in the Philippines regarding the existence of this tumor. In this paper, we present a case of a 70-year-old elderly female who had a 10-year history of a gradually enlarging left lateral neck mass. Histopathologic examination showed a tumor arranged of cords, nests, and trabeculae of monomorphic round cells with abundant clear to lightly eosinophilic cytoplasm surrounded by thick hyalinized collagen bundles. Immunohistochemistry and molecular studies were done which revealed a positive p63 staining, negative SMA and S100, and an EWSR1 rearrangement in Fluorescence in situ hybridization (FISH), thus, confirming the diagnosis.

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL). Classification of DLBCL is often based on the cell of origin (COO), distinguishing between germinal center B-cell (GCB) and non-GCB subtypes. Although not yet recognized as a distinct entity by the World Health Organization (WHO), double expressor lymphoma (DEL), characterized by the co-expression of c-MYC and BCL2, carries an unfavorable prognosis for a subgroup of DLBCL patients. Another entity is the so-called high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (double-hit/triple-hit lymphomas) diagnosed through fluorescent in-situ hybridization (FISH) analysis.

This study aimed to determine the clinicopathologic profile and survival outcomes of Filipino DLBCL patients at the Philippine General Hospital (2016-2021), comparing double-hit versus non-double-hit and doubleexpressor versus non-double-expressor lymphomas, and assessing concordance between FISH-measured double-hit and IHC-measured double-expressor statuses.

This is a single-arm, retrospective cohort study involving all surgical pathology cases signed out, with the aid of immunohistochemistry (IHC) studies, as NHL DLBCL, GCB, or non-GCB subtype, from 2016 to 2021. A second panel of IHC studies and FISH analysis using tissue microarray was subsequently done. Most cases exhibited a nonGCB subtype and were classified as DEL on second IHC panel. Five out of eleven DEL cases were reclassified as double hit lymphoma (DHL).

Clinically, most patients with these lymphomas present at age 60 years and below, exhibit B symptoms, with elevated serum lactate dehydrogenase (LDH) levels, at least stage III-IV disease at diagnosis, and possess a high International Prognostic Index (IPI) score, collectively indicating a poor prognosis.

Survival outcomes for patients with DLBCL ranges from three to 37 months. All cases of mortality were associated with DEL, contrasting with DHL cases which had variable outcomes. Due to limited sampling, statistical significance of the results cannot be determined. A comprehensive evaluation is essential to the diagnosis of DLBCL and DHL to include a complete immunohistochemistry panel and molecular testing, notably with FISH studies.

Gliomatosis peritonei (GP) is a condition characterized by the dissemination of mature glial tissues throughout the peritoneal cavity. It is usually associated with immature ovarian teratoma but presents with mature cystic teratoma (MCT) in 1% of cases. GP, associated with MCT, is a benign disorder. The majority of cases remain asymptomatic and rarely recur. Here, we present a case of a 22-year-old woman with a history of abdominal enlargement and severe abdominal pain who underwent exploratory laparotomy, peritoneal fluid cytology, bilateral salpingo-oophorectomy, appendectomy, omental biopsy, and Jackson-Pratt drain insertion with histopathologic result of GP with MCT. A month later, the patient had a recurrence of abdominal enlargement, necessitating a second surgery. Immunohistochemistry for histopathologic evaluation and diagnostic imaging are crucial in confirming the diagnosis and guiding the treatment strategy. A multidisciplinary team approach in monitoring and comprehensive support is significant in optimizing outcomes for patients with aggressive GPs associated with MCT. Further research and clinical experience are essential to establish a standardized guideline to improve the management and clinical outcome of this condition.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare neoplasm of the kidney. Recognition of this rare entity is important with regards to a patient’s prognosis and therapeutic management.
Kidney Neoplasms ; Immunohistochemistry ; Pathology, Surgical

Nephroblastoma is an uncommon renal malignancy primarily observed in the pediatric population, with its occurrence in adults being exceedingly infrequent. We describe an extremely rare case of a malignant embryonal tumor presenting in an adult patient with right renal mass. Final histopathologic diagnosis was nephroblastoma with favorable histology. Use of immunohistochemistry studies is generally unnecessary but its rarity in the adult population raises uncertainty in diagnosing this malignancy by histomorphology alone.

Humans ; Female ; Receptors, Estrogen/metabolism* ; Breast Neoplasms/metabolism* ; Receptors, Progesterone/metabolism* ; Immunohistochemistry ; Estrogen Receptor alpha

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL). Classification of DLBCL is often based on the cell of origin (COO), distinguishing between germinal center B-cell (GCB) and non-GCB subtypes. Although not yet recognized as a distinct entity by the World Health Organization (WHO), double expressor lymphoma (DEL), characterized by the co-expression of c-MYC and BCL2, carries an unfavorable prognosis for a subgroup of DLBCL patients. Another entity is the so-called high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (double-hit/triple-hit lymphomas) diagnosed through fluorescent in-situ hybridization (FISH) analysis. Objective: This study aimed to determine the clinicopathologic profile and survival outcomes of Filipino DLBCL patients at the Philippine General Hospital (2016-2021), comparing double-hit versus non-double-hit and doubleexpressor versus non-double-expressor lymphomas, and assessing concordance between FISH-measured double-hit and IHC-measured double-expressor statuses. Methods: This is a single-arm, retrospective cohort study involving all surgical pathology cases signed out, with the aid of immunohistochemistry (IHC) studies, as NHL DLBCL, GCB, or non-GCB subtype, from 2016 to 2021. A second panel of IHC studies and FISH analysis using tissue microarray was subsequently done. Most cases exhibited a nonGCB subtype and were classified as DEL on second IHC panel. Five out of eleven DEL cases were reclassified as double hit lymphoma (DHL). Results: Clinically, most patients with these lymphomas present at age 60 years and below, exhibit B symptoms, with elevated serum lactate dehydrogenase (LDH) levels, at least stage III-IV disease at diagnosis, and possess a high International Prognostic Index (IPI) score, collectively indicating a poor prognosis. Conclusion Survival outcomes for patients with DLBCL ranges from three to 37 months. All cases of mortality were associated with DEL, contrasting with DHL cases which had variable outcomes. Due to limited sampling, statistical significance of the results cannot be determined. A comprehensive evaluation is essential to the diagnosis of DLBCL and DHL to include a complete immunohistochemistry panel and molecular testing, notably with FISH studies.
lymphoma ; lymphoma, large B-cell, diffuse ; cytogenetics ; immunohistochemistry

Solid pseudopapillary neoplasm (SPN) is a rare pancreatic neoplasm. This case reports a 63-year-old female previously diagnosed with bilateral adrenocortical carcinoma post resection who presents with persistent epigastric pain. Suspicions for recurrence prompted diagnostics revealing retropancreatic and left suprarenal foci, both suspicious for malignancy. Resection of both tumors yielded a moderately to poorly differentiated retropancreatic carcinoma with differentials not limited to recurrence and pancreatic neuroendocrine tumor with a left suprarenal lymph node. Immunohistochemistry was then done and was consistent with SPN having a strong expression for b-catenin, vimentin, pancytokeratin. It was non-specific to melan-A and negative for chromogranin A, synaptophysin, inhibin-a and CD10. At 6 months’ follow up, patient is clinically well and abdominal CT scan showed no recurrence. SPNs can masquerade as other neoplasms having similar clinical, radiologic and histopathologic features. Immunohistochemistry thus plays a crucial role for accurate diagnosis and management. Surgical resection still remains the treatment of choice and can provide a 95% overall survival rate, while limited evidence supports the use of adjuvant chemotherapy or radiation.
Immunohistochemistry

Background: Guidelines for testing human epidermal growth factor receptor 2 (HER2) in breast cancer using fluorescence in situ hybridization (FISH) were released in 2018. These guidelines were jointly developed by the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) to achieve a clearer designation of breast cancer HER2 status. Clinical correlation with other factors was also considered appropriate, especially for those cases classified under ISH groups 2, 3, and 4. Objective: In this study, we examined clinicopathologic features among Filipino breast cancer patients whose HER2 status was reclassified based on the 2018 ASCO/CAP guidelines. Methodology: One hundred and thirty-two (132) breast cancer cases with immunohistochemistry (IHC) equivocal results in the Medical City were enrolled from January 2017 up to December 2020. HER2 FISH results classified under groups 2, 3, and 4 were then re-evaluated for HER2-IHC status in accordance with the 2018 ASCO/CAP guidelines. The relationship between clinicopathologic features and HER2 status was analyzed using the Fisher exact test. Results: Significant differences were found in histologic type, nuclear pleomorphism, mitotic rate, progesterone receptor (PR) status, and regional lymph node involvement among the reclassified ISH groups. In the conv+ group, the tumor cells did not involve the regional lymph nodes as compared to group 5, where the tumor cells were involved. The conv- group had a higher grade for nuclear pleomorphism, mitotic count, and overall Nottingham Histologic Grade than group 5. There was a significant association between progesterone receptors among the conv- group and group 1. Conclusion Filipino breast cancer cases whose HER2 status was reclassified to negative following the 2018 ASCO/CAP guidelines had statistically different clinicopathologic features from those classified as group 5.
Breast Neoplasms ; Immunohistochemistry

Extraskeletal Ewing sarcoma (EES) is a rare tumor that primarily affects children and lacks specific clinical signs. Diagnosis is confirmed through imaging techniques, histology, and molecular diagnostics. Treatment typically involves surgical intervention and chemotherapy. We present the case of a 15-year-old female with a history of abnormal mass enlargement in the right flank area. An initial diagnosis of Wilms tumor was made, and the patient underwent a right open radical nephrectomy. However, the tumor recurred eight months after nephrectomy, necessitating a metastasectomy. Chemotherapy was started to immediately target the tumor recurrence. Next-generation sequencing done on the open radical nephrectomy and metastasectomy samples revealed the presence of the EWSR1-FLI1 fusion gene in both specimens, confirming the final diagnosis to be primary renal Ewing sarcoma. Despite undergoing a right open radical nephrectomy for the primary tumor site, a metastasectomy during tumor recurrence, and chemotherapy, the patient’s prognosis remained poor.
Immunohistochemistry ; Drug Therapy