Variety Of Histologic Patterns Research Articles

Post-Transplant Glomerulonephritis: Challenges and Solutions.

Glomeruli can be damaged in several conditions after kidney transplantation, with a potential impact on the graft function and survival. Primary glomerulonephritis, a group of glomerular immunological damage that results in variable histological patterns and clinical phenotypes, can occur in kidney transplant recipients as a recurrent or de novo condition. Specific immunologic conditions associated with kidney transplantation, such as acute rejection episodes, can act as an additional trigger after transplantation, impacting the incidence of these glomerulopathies. The post-transplant GN recurrence ranges from 3% to 15%, varying according to the GN subtype and post-transplant time, mainly occurring after 3-5 years of kidney transplantation. Advances in the knowledge of glomerulonephritis pathophysiology have provided new approaches to pre-transplant risk evaluation and post-transplant monitoring. Glomeruli can be affected by several systemic viral infections, such as human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV), severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), cytomegalovirus (CMV), and BK virus. The diagnosis of these infections, as well as the identification of possible complications associated with them, are important to minimize the negative impacts of these conditions on kidney transplant recipients' outcomes.

Variant histology of pediatric nodular lymphocyte-predominant Hodgkin lymphoma with IgD and CD30 expression.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), recently known as nodular lymphocyte-predominant B-cell lymphoma (NLPBL), accounts for 5%-10% of Hodgkin lymphoma (HL). Different morphologic patterns of NLPBL are identified and categorized as typical patterns (type A and B) and variant histologic patterns (types C, D, E, and F). We investigated different morphologic patterns, CD30 and IgD expression in pediatric patients with NLPBL diagnosed at the Children's Cancer Hospital Egypt. Forty-six (53%) of the patients exhibited a typical histologic pattern, whereas the remaining (47%) exhibited variant histologic pattern. Variant histology is associated with unfavorable clinical characteristics, such as advanced stages, B-symptoms, and extranodal involvements, particularly bone marrow and bone infiltration, with p-values of .06, .05, and 0.01%, respectively. Additionally, 39% of patients with variant histology experienced disease progression or relapse, compared to only 15.2% of patients with typical patterns (p=.009). Types C and D are related to decreased event-free survival (EFS), as shown by a p-value of .05. The 5-year EFS for patients with variant histology was 94.4% for the rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisone (RCHOP) versus 33.3% for the adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD). IgD expression in lymphocyte-predominant (LP) cells was detected in 44 (50%) patients, while CD30 expression in LP cells was found in 39 (44%) patients. Variant histology of NLPBL was associated with advanced disease stages and a poor prognosis, while expression of IgD and CD30 in LP cells was not. The poor outcome of variant histology improved with the RCHOP regimen.

Low-Grade Myofibroblastic Sarcoma of the Oral and Maxillofacial Region: An International Clinicopathologic Study of 13 Cases and Literature Review.

Low-grade myofibroblastic sarcoma (LGMS) represents an atypical tumor composed of myofibroblasts with a variety of histological patterns and with a high tendency to local recurrence and a low probability of distant metastases. LGMS has predilection for the head and neck regions, especially the oral cavity.This study aimed to report 13 new cases of LGMS arising in the oral and maxillofacial region.This study included LGMS cases from five oral and maxillofacial pathology laboratories in four different countries (Brazil, Peru, Guatemala, and South Africa). Their clinical, radiographic, histopathological, and immunohistochemical findings were evaluated.In this current international case series, most patients were females with a mean age of 38.7 years, and commonly presenting a nodular lesion in maxilla. Microscopically, all cases showed a neoplasm formed by oval to spindle cells in a fibrous stroma with myxoid and dense areas, some atypical mitoses, and prominent nucleoli. The immunohistochemical panel showed positivity for smooth muscle actin (12 of 13 cases), HHF35 (2 of 4 cases), β-catenin (3 of 5 cases), desmin (3 of 11 cases), and Ki-67 (range from 5 to 50%). H-caldesmon was negative for all cases. The diagnosis of LGMS was confirmed in all cases.LGMS shows predominance in young adults, with a slight predilection for the female sex, and maxillary region. LGMS should be a differential diagnosis of myofibroblastic lesions that show a proliferation of spindle cells in a fibrous stroma with myxoid and dense areas and some atypical mitoses, supporting the diagnosis with a complementary immunohistochemical study. Complete surgical excision with clear margins is the treatment of choice. However, long-term follow-up information is required before definitive conclusions can be drawn regarding the incidence of recurrence and the possibility of metastasis.

A Rare Case of Metastatic Extragonadal Yolk Sac Tumor – A Challenging Diagnosis on Cytomorphology

Abstract Introduction/Objective Yolk sac tumors are characterized by variable histologic patterns and broad cytologic spectrum; thereby making the distinction from a poorly differentiated adenocarcinoma in a metastatic site extremely challenging. We present cytology and histology of a metastatic extragonadal germ cell tumor with predominant solid yolk sac component. Methods/Case Report 36-year-old male presented with bilateral supraclavicular masses (right: 6 x 7 cm, left: 3 x 4 cm). CT chest and abdomen revealed large mediastinal and hilar nodal mass (11.6 cm), right hilar mass (8.5 cm), bilateral heterogeneous adrenal masses (right: 11.4 cm, left: 3.1 cm), and an enhancing retroperitoneal implant. Differential diagnoses of lymphoma, adrenocortical carcinoma, small cell lung carcinoma, and metastatic germ cell tumor were considered. Testicular ultrasound revealed no masses. Fine needle aspiration of supraclavicular lymph nodes showed highly cellular smears comprised of tumor cells, dispersed singly and in clusters, with irregular nuclear contours, increased nuclear to cytoplasmic ratio, coarse chromatin, occasional prominent nucleoli, and vacuolated cytoplasm. Tumor cells were positive for KRT7 and TTF-1, and negative for p40 and PAX8. A diagnosis of metastatic poorly differentiated carcinoma was rendered. Subsequent excisional biopsy of the lymph node showed a metastatic tumor with tumor cells similar to those seen in cytology, appearing in solid sheets with focal papillary architecture, replacing the entire lymph node. Additional immunohistochemistry showed expression of SALL4, Glypican 3, with lack of expression for OCT3/4, AFP, hCG, and CD30, supporting the diagnosis of metastatic yolk sac tumor, solid pattern. Results (if a Case Study enter NA) NA. Conclusion Aggressive clinical presentation, broad clinical differential diagnoses, rarity of a primary mediastinal yolk sac tumor, non-diagnostic cytomorphology along with expression of divergent differentiation markers (TTF-1 in our case) makes a definitive diagnosis of metastatic extragonadal yolk sac tumor extremely challenging. High index of clinical suspicion is required for a definitive diagnosis on cytomorphology.

Update in Pathology of Practically Encountered Lesions and Diseases in the Liver

This issue of the American Journal of Surgical Pathology, Reviews and Reports is devoted to recent advances and update in the pathology of the liver. The articles provide insights into the current nomenclature, classification, diagnosis, differential diagnoses, clinical and prognostic aspects of various liver diseases, and lesions that are informative to pathologists in their daily practice. Hepatocellular adenomas (HCAs) is generally a benign liver neoplasm that typically arises in the noncirrhotic liver; however, malignant transformation does occur, and hence, subtyping is critical. Drs Jung and Liu present a case of HCA that was initially diagnosed as inflammatory HCA on a biopsy and subsequently was confirmed to be β-catenin–activated inflammatory HCA on the resection specimen. They then comprehensively review recent updates on molecular classification and the key histologic features of each subtype and discuss common diagnostic pitfalls. Over the past decades, hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) have been recognized to be heterogeneous in morphology, molecular features, and biological behavior. Recent World Health Organization classification describes various histomorphological subtypes of HCC and iCCA, some with characteristic molecular profiles, clinical correlates, and prognostic implications. In their review, Drs Hwang and Kim nicely discuss recently described subtypes of HCC and iCCA: macrotrabecular HCC, steatohepatitic HCC, scirrhous HCC, and small duct iCCA. Congestive hepatopathy shows a unique pattern of fibrosis, that is, pericentral fibrosis at early stage, which may progress to bridging fibrosis and cirrhosis. Making a diagnosis of congestive hepatopathy and staging its fibrosis are important tasks for pathologists, as patients may undergo liver biopsies before cardiac transplantation to assess the degree of liver fibrosis, which may impact clinical decision-making. Besides patients' own cardiac dysfunction, congestive hepatopathy can also be seen after a Fontan procedure. Drs Gosse and Bosch describe a case of congestive hepatopathy due to altered circulation with a Fontan procedure. They then discuss the fibrosis scoring systems recently described for Fontan-associated liver disease and congestive heart disease–associated hepatopathy. Combined hepatocellular-cholangiocarcinoma is a rare primary liver tumor with neoplastic components of both hepatocytic and cholangiocytic differentiation within the same tumor. There is recent consensus paper and World Health Organization classification of this unique tumor. Drs Kondo, Akiba, and Yano herein report a case of this tumor and thoughtfully review the terminology, classification, and clinical and pathological characteristics of combined hepatocellular-cholangiocarcinoma and its differential diagnosis. Hemophagocytic lymphohistiocytosis is a rare disease with a high mortality. Liver involvement is common, with most patients demonstrating acute hepatitis. Therefore, liver biopsies are frequently performed when this entity is suspected. Dr Xiong and colleagues summarize the clinical features of hemophagocytic lymphohistiocytosis, emphasizing its hepatic manifestations. They describe the highly variable histologic patterns and address difficulties encountered by pathologists. We are extremely grateful to all the contributors for sharing their expertise and knowledge in forming this issue. We hope that the information provides highlights and elucidates the practically encountered lesions in the liver. Guest Editors

3D analyses reveal T cells with activated nuclear features in T-cell/histiocyte-rich large B-cell lymphoma

AbstractNodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) can show variable histological growth patterns and present remarkable overlap with T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL). Previous studies suggest that NLPHL histological variants represent progression forms of NLPHL and THRLBCL transformation in aggressive disease. Since molecular studies of both lymphomas are limited due to the low number of tumor cells, the present study aimed to learn if a better understanding of these lymphomas is possible via detailed measurements of nuclear and cell size features in 2D and 3D sections. Whereas no significant differences were visible in 2D analyses, a slightly increased nuclear volume and a significantly enlarged cell size were noted in 3D measurements of the tumor cells of THRLBCL in comparison to typical NLPHL cases. Interestingly, not only was the size of the tumor cells increased in THRLBCL but also the nuclear volume of concomitant T cells in the reactive infiltrate when compared with typical NLPHL. Particularly CD8+ T cells had frequent contacts to tumor cells of THRLBCL. However, the nuclear volume of B cells was comparable in all cases. These results clearly demonstrate that 3D tissue analyses are superior to conventional 2D analyses of histological sections. Furthermore, the results point to a strong activation of T cells in THRLBCL, representing a cytotoxic response against the tumor cells with unclear effectiveness, resulting in enhanced swelling of the tumor cell bodies and limiting proliferative potential. Further molecular studies combining 3D tissue analyses and molecular data will help to gain profound insight into these ill-defined cellular processes.

OLIG2 immunolabeling in feline ependymoma.

Ependymoma, one of the most common gliomas in cats, occurs most often in the lateral and third ventricles and has variable histologic patterns that often form rosettes and pseudorosettes. Oligodendrocyte transcription factor (OLIG2) is expressed in oligodendrocyte precursor cells and mature oligodendrocytes. Although widely used as a diagnostic marker for most gliomas, OLIG2 is reported to have minimal immunolabeling in ependymomas. Here we characterize the OLIG2 immunolabeling pattern in 19 cases of feline ependymoma, which occurred predominantly in the lateral and third ventricles. Immunohistochemistry for GFAP was variable in 14 cases and was typically localized in the cytoplasmic processes of the neoplastic ependymal cells, especially in the rosettes and pseudorosettes. Nuclear OLIG2 immunolabeling was present in 17 cases and varied in intensity from weak (4 cases) to strong (13 cases). The distribution of OLIG2 immunolabeling within the neoplasms included none (2 cases), <25% (7 cases), 25-50% (6 cases), 51-75% (2 cases), and >75% (3 cases). OLIG2 immunolabeling intensity and distribution is widespread in feline ependymoma, in contrast to ependymomas in other species, and should not be relied upon as a specific marker for feline oligodendroglioma.

Amyloid cast nephropathy: A rare presentation of multiple myeloma–associated light chain amyloidosis

Introduction: Monoclonal immunoglobulins can cause a variety of histologic patterns of kidney injury, depending on the physicochemical properties. Multiple myeloma manifests more often as light-chain nephropathy. On the other hand, light-chain amyloidosis leads to glomerular and vascular amyloid deposits, but a less common presentation with amyloid casts has also been described. Rarely, more than one histologic pattern can be present in the same patient. Case report: We report a case of a 73-year-old man, diagnosed with multiple myeloma that 8 months after achieving partial response to chemotherapy develops acute kidney injury and nephrotic syndrome. Kidney biopsy revealed features of light-chain nephropathy, amyloid cast nephropathy, and glomerular and vascular amyloid deposits. Immunofluorescence was positive for IgA (++) and lambda chains (+++) and negative for kappa chains. After the diagnosis of multiple myeloma-associated light-chain amyloidosis, chemotherapy was initiated; unfortunately, the patient died 1 month after the diagnosis. Conclusion: Amyloid casts, isolated or accompanied by other renal or extra-renal amyloid deposits, are another form of tubular toxicity caused by dysproteinemias and should be systematically screened in kidney biopsies.

Hepatic Secondary Syphilis Can Cause a Variety of Histologic Patterns and May Be Negative for Treponeme Immunohistochemistry.

The rate of syphilis in the United States has been increasing steadily in the past decade, but it remains an uncommon diagnosis in tissue biopsies. Most of the pathology literature on hepatic syphilis consists of older series or case reports. This study aimed to systematically characterize the histologic spectrum of hepatic syphilis in a contemporary cohort. Clinicopathologic features of 14 hepatic syphilis cases between 2012 and 2018 were analyzed to characterize the broad spectrum of histologic changes. Thirteen patients were men (age range: 19 to 59 y); 6 had known human immunodeficiency virus, 7 were men known to have sex with men, and no patient had known prior syphilis. Hepatic syphilis was the primary clinical suspicion in only 1 patient. Common symptoms included jaundice, rash, and abdominal pain. Thirteen had elevated transaminases, and 12 had elevated alkaline phosphatase. Pathologic changes were grouped into 5 histologic patterns: biliary-pattern injury (n=5), acute hepatitis (n=4), autoimmune hepatitis-like (n=1), fibroinflammatory mass-forming lesion (n=2), and no particular pattern (n=2). Nearly all showed portal and lobular lymphocytes and plasma cells; 12 had prominent histiocytes/Kupffer cells, 9 had ductular reaction, and 7 had duct inflammation. Occasional focal findings included dropout (n=7), phlebitis (n=7), and loose granulomata (n=5). Treponeme immunohistochemistry was positive in 10 and negative in 4, though treatment was given before biopsy in 3 of those 4. Thirteen patients had rapid plasma reagin testing either before or after biopsy, with 1:64 or higher titer. All patients who received treatment recovered. Hepatic syphilis is rare but likely underrecognized. It exhibits a variety of histologic appearances and therefore should be considered in several hepatic differential diagnoses, especially in men who have sex with men. Kupffer cells, granulomata, and phlebitis may suggest the diagnosis regardless of predominant histologic pattern. Negative treponeme immunohistochemical staining does not exclude the diagnosis, including in untreated patients.

Benign vs malignant pancreatic lesions: Molecular insights to an ongoing debate.

Several benign conditions such as chronic pancreatitis, autoimmune pancreatitis, and paraduodenal pancreatitis can present as mass lesions and may mimic pancreatic ductal adenocarcinoma (PDAC) clinically and radiologically. Thorough histologic examination with attention to certain morphologic features can assist in deciphering neoplastic from reactive, however small biopsies often remain a challenge. Variable histologic patterns in conventional PDAC may also confound the diagnosis of PDAC. Uncommon subtypes of pancreatic carcinoma such as adenosquamous and squamous cell carcinoma, colloid carcinoma, medullary carcinoma, hepatoid carcinoma and signet ring cell carcinoma necessitate excluding metastasis from other sites prior to rendering the diagnosis of pancreatic carcinoma. The use of immunohistochemical staining and molecular markers can aid in separating benign from malignant and PDAC from metastasis. PDAC expresses a few non-specific epithelial and mucin immunomarkers such as CK7, CK19, MUC1, MUC4 and MUC5AC. However, the only immunohistochemical marker that is specific for PDAC in the right clinical context is SMAD4. Loss of SMAD4 within atypical glands and ducts supports the diagnosis of PDAC in a limited sample. Unfortunately, this finding is seen only in 50% of PDAC cases. The identification of certain mutations can help support a diagnosis of PDAC when benign conditions are in the differential. At the molecular level, KRAS oncogene mutations are seen in approximately 93% of PDACs. Subsequent neoplastic progression is driven by additional mutations of tumor suppressor genes, such as CDKN2A, TP53, and SMAD4. Molecular markers can also provide an insight to the prognosis. For instance, the loss of SMAD4 is associated with a poor outcome whereas mutations in MLL, MLL2, MLL3, and ARID1A are associated with improved survival.

Case of Metastatic Malignant Melanoma Simulating Granuloma Annulare

Malignant melanoma and particularly metastatic melanoma represent a diagnostic challenge due to the wide variety of histologic patterns, resemblance to benign entities, and extensive range of clinical presentations. A high index of suspicion for melanoma is important for accurate diagnosis, especially when there is a previous history of malignancy. Here, we present a patient with a history of melanoma and locally metastatic melanoma, who subsequently developed a nodule on his right forearm near the site of his previous melanoma excision. Histologically, the melanoma appeared as granuloma annulare (GA) with benign cytologic features, but was identified as metastatic melanoma using SOX-10 immunohistochemical staining. Other malignancies, including lymphomas, leukemias, sarcomas, and cutaneous metastases of internal malignancies, have mimicked GA and interstitial granulomatous processes. Therefore, further immunohistochemical staining should be performed to assess for metastatic disease in the setting of a histological pattern that resembles a benign granulomatous process in a patient with a history of malignancy, including malignant melanoma.

Rhabdomyosarcoma: From Obscurity to Clarity in Diagnosis … But With Ongoing Challenges in Management: The Farber-Landing Lecture of 2020.

Rhabdomyosarcoma, the most common soft tissue sarcoma in childhood, has challenged and intrigued soft tissue pathologists ever since the original descriptions. Once based on the identification of rhabdomyoblastic cells with elongate eosinophilic cytoplasm, the diagnosis has evolved to include tumors composed only of primitive mesenchymal cells but now relies heavily on immunohistochemical stains for desmin, myogenin, and MyoD. Rhabdomyosarcomas show a variety of histological patterns, giving rise to classifications that have included embryonal, alveolar, botryoid, pleomorphic, spindle cell, and sclerosing subtypes. These have been linked to prognosis and treatment assignment in the past, but that concept has been superseded by the identification of PAX3-FOXO1 or PAX7-FOXO1 fusions. Fusion testing results are more predictive of outcome and have become standard practice in clinical management. However, high risk tumors with alveolar histology or metastatic disease continue to resist oncologic treatment.

Neuroendocrine neoplasms of lung, pancreas and gut: a morphology-based comparison.

The bronchopulmonary (BP) and gastroenteropancreatic (GEP) organ systems harbor the majority of the neuroendocrine neoplasms (NENs) of the body, comprising 20 and 70% of all NENs, respectively. Common to both NEN groups is a classification distinguishing between well- and poorly differentiated NENs associated with distinct genetic profiles. Differences between the two groups concern the reciprocal prevalence of well and poorly differentiated neoplasms, the application of a Ki67-based grading, the variety of histological patterns, the diversity of hormone expression and associated syndromes, the variable involvement in hereditary tumor syndromes, and the peculiarities of genetic changes. This review focuses on a detailed comparison of BP-NENs with GEP-NENs with the aim of highlighting and discussing the most obvious differences. Despite obvious differences, the principle therapeutical options are still the same for both NEN groups, but with further progress in genetics, more targeted therapy strategies can be expected in future.

CD20-Negative Nodular Lymphocyte-Predominant Hodgkin Lymphoma: A 20-Year Consecutive Case Series From a Tertiary Cancer Center.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare, indolent Hodgkin lymphoma subtype with distinct clinicopathologic features and treatment paradigms. The neoplastic lymphocyte-predominant cells typically express bright CD20 and other B-cell antigens, which distinguishes them from Hodgkin/Reed-Sternberg cells of lymphocyte-rich classic Hodgkin lymphoma. To characterize the clinicopathologic features of CD20-negative NLPHL at a single institution. A retrospective search for CD20-negative NLPHL in our pathology archives and medical records was conducted. Of 486 NLPHL patients identified with CD20 available for review, 14 (2.8%) had LP cells with absent CD20 expression. Patients with prior rituximab administration (n = 7) and insufficient clinical history (n = 1) were excluded, leaving 6 patients with rituximab-naïve, CD20-negative NLPHL. A broad immunohistochemical panel showed the LP cells in all cases expressed B-cell antigens, particularly Oct-2, although PAX5 and CD79a were frequently also dim. CD30, CD15, and Epstein-Barr virus-encoded small RNAs were negative in all evaluated cases. Two patients had high-risk variant immunoarchitectural pattern D. One patient had extranodal disease, involving the spleen and bone, and was suspected to have large cell transformation. Standard NLPHL therapy was given, including local radiation and/or chemotherapy. Of 5 patients with available follow-up, 4 are alive in complete remission after therapy, and 1 is alive with relapsed disease. NLPHL can lack CD20 de novo without prior rituximab therapy. In such cases, extensive immunophenotyping helps distinguish NLPHL from lymphocyte-rich classic Hodgkin lymphoma, which differ in clinical behavior and therapy. In our series, CD20-negative NLPHL showed both classic and variant histologic patterns and the expected range of clinical behavior seen in NLPHL, including 1 case with suspected large cell transformation.

Bone Marrow Involvement in Patients With Nodular Lymphocyte Predominant Hodgkin Lymphoma.

The spectrum of bone marrow lesions in patients with nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) has not been evaluated systematically. In this study, we analyzed a cohort of 262 NLPHL patients who underwent staging bone marrow evaluation or targeted bone biopsy as a part of their initial diagnostic workup, among which lymphoma was detected in 24 (9.2%) patients. Eleven patients had bone marrow findings of NLPHL (few large B cells in a background of small B cell and T cell), and 13 patients had either T-cell/histiocyte-rich large B-cell lymphoma (large B cells in a background of T cells and histiocytes) or typical diffuse large B-cell lymphoma (sheets of large B cells). Bone marrow involvement was more common in patients with variant NLPHL histologic patterns in the lymph node as compared with those who had classic patterns (12/18 vs. 4/16; P=0.02). An additional 27 NLPHL patients had bone marrow specimens involved by lymphoid aggregates composed of small T cells and B cells without large B cells; this subgroup had a longer event-free survival than patients with lymphoma in the bone marrow (145 vs. 35 mo). Disease recurrence or progression was more frequent in patients with bone marrow involvement by either NLPHL or LBCL, compared with patients who had lymphoid aggregates (13/21 vs. 8/26; P=0.04). In conclusion, staging bone marrow sampling detects lymphoma in a sizeable subset of NLPHL patients, particularly those with variant histologic patterns. Lymphoid aggregates lacking large B cells in staging bone marrow specimens from NLPHL patients can be regarded as clinically benign without impact on stage, outcome, or risk stratification.

Unusual Presentations of Gynecologic Tumors: Primary, Extrauterine, Low-Grade Endometrioid Stromal Sarcoma.

- Low-grade endometrial stromal sarcomas, when uterine in location, are relatively easy to diagnose because of characteristic morphology and patterns of myometrial invasion. However, when they occur at extrauterine sites, they fall under the broad umbrella of small round blue cell tumors, making diagnosis challenging, especially when they have variant morphologic features and lack the characteristic pattern of invasion. - To provide an insight into the sites of occurrence of low-grade endometrioid stromal sarcomas, the variant morphologic patterns, clues to diagnosis, and the usefulness of immunohistochemistry as an aid to facilitate correct diagnosis. The outcome of these tumors, in comparison with their uterine counterpart, is also discussed. - Existing peer-reviewed literature was reviewed. - Low-grade endometrioid stromal sarcoma is an uncommon neoplasm that can be misdiagnosed because of its rarity, unusual location, and presence of numerous variant histologic patterns that mimic other tumors. Knowledge of those features; consideration of this tumor in the differential diagnosis of small, round blue cell tumors at any location in a woman; and an appropriate use of immunohistochemistry can help facilitate the diagnosis.

Submandibular gland cancer: Specific features and treatment considerations.

In the absence of unified treatment protocol, we evaluated the management and outcomes of submandibular gland cancers in an unselected patient series. We included all patients with resected submandibular gland cancer treated at the Helsinki University Hospital from 2000 to 2010 with a 5-year minimum follow-up. Twenty-five patients with cancer represented 30% of submandibular gland neoplasms, and most were adenoid cystic carcinomas (ACCs; 56%). At presentation, 3 patients showed clinical signs of probable malignancy. Of 22 neck dissection specimens, 5 patients (20%) had metastases with an occult metastasis rate of 4%. Cancer recurred in 11 patients (44%), of which 7 (28%) were only at a distant site. The 5-year disease-specific survival (DSS) and overall survival (OS) rates were 76%, and disease-free survival (DFS) was 68%. Most tumors were ACCs differing from the histological pattern of parotid gland cancers. Occult metastases were rare. The rarity of submandibular gland cancer, its variable histological pattern, and varying biological behavior warrant centralized management.

SINONASAL TERATOCARCINOSARCOMA - A RARE CASE REPORT

Sinonasal teratocarcinosarcoma is a rare and highly malignant tumor characterized by complex admixture of teratomatous and carcinosarcomatous component. Here, we report a case of 72-year-old male presented with complaints of epistaxis, recurrent sinusitis, nasal stuffiness, and nasal blockade for past 5-6 months and his computed tomography report revealed as an inflammatory sinonasal disease with polyposis. Histopathology examination showed fragments of upper respiratory mucosa admixed with fragments of tumor composed of benign and malignant counterparts of both epithelial and mesenchymal components in a variety of histologic patterns. Also noted were the characteristic squamous epithelium with “fetal-type” clear cells, areas of necrosis, mitotic figure and sheets of undifferentiated blastemal like cells. Immunohistochemistry demonstrated positive staining for cytokeratin, epithelial membrane antigen, vimentin, synaptophysin, S-100, chromogranin, and CD99. This polyimmunophenotypic characteristic and diverse histological differentiation provided the basis for the diagnosis. Knowing its highly aggressive behavior, the patient should be treated aggressively and followed up closely. Key words: Carcinosarcom, Fetal epithelium, Polyimmunophenotypic, Teratoid

Neuroendocrine Tumors of the Breast.

A small but increasingly recognized and studied subset of breast carcinomas are characterized by neuroendocrine (NE) differentiation. As with nearly all forms of breast neoplasia, NE tumors are characterized by considerable heterogeneity in microscopic appearance and clinical aggressiveness. About half of NE breast carcinomas recapitulate the histological spectrum typical of their counterparts in other organ systems, varying from "carcinoid-like" to small cell carcinoma, with most representing intermediate grade tumors. Despite NE morphology, these tumors have a high frequency of estrogen receptor expression. Clinical outcomes of women with NE breast carcinomas are reliably grade and stage dependent. Tumors associated with "solid papillary" differentiation comprise the remaining cases of NE breast neoplasia. Solid papillary carcinoma is an intrinsically low grade/favorable prognosis class of breast neoplasia that usually presents in post-menopausal age groups. About half of solid papillary carcinoma present as a distinctive pattern of ductal carcinoma in situ that may be difficult to recognize owing to its close resemblance to florid proliferative lesions. Invasive solid papillary carcinomas are characterized by a variety of histological patterns and often show mucinous differentiation. Future studies are necessary to better define the histogenesis, optimal classification, and improved directed therapies for NE breast neoplasia.

Primary pleural thymoma mimicking signs of another tumor

&lt;p&gt;A team of Italian researchers recently reported an unusual case of the tumor of the thymus, manifesting test results that are similar to another tumor, thus underscoring the imperative need for a better awareness of clinical results among physicians in order to avoid misdiagnosing their cancer patients. &lt;br /&gt; &lt;br /&gt;The thymus gland, located in the anterior mediastinum (under the breastbone in the chest cavity) is an organ that produces infection-fighting lymphocytes – subsequently called T-cells – and it is most active during childhood and then atrophies in adulthood. The cancer of the thymus, called thymoma, is an uncommon form of neoplasm; according to the American Society of Clinical Oncology, less than one person per 1.5 million people develops thymoma. Moreover, “[t]he occurrence of thymoma outside the mediastinum is a rare event,” described a case report published in this issue of AMOR by Roberto Monaco, Antonietta D’Alterio, Raffaella Lucci, and Oscar Nappi from the pathology departments of Cardarelli Hospital and University of Naples Federico II in Naples, Italy. While thymomas occurring at unusual sites such as the neck, lung, and thyroid have been occasionally observed, existing literature rarely reports thymomas affecting the pleural, i.e. the thin and delicate layers of membranes that wrap, cushion, and protect the lungs. &lt;br /&gt; &lt;br /&gt;In the case of their patient, the authors described, “Diagnostic imaging showed that the pleural tumor encased the entire left lung.” The specimen biopsied from the tumor showed signs that were consistent with thymoma. However, the surgical exploration of the anterosuperior mediastinum found no evidence of a thymic tumor, which led Monaco and his fellow researchers to believe that the thymoma may have originated from an abnormal thymic tissue in the pleura, and then likely developed as a separate lesion that spreads along the pleural in ways similar to a diffuse mesothelioma afflicting the linings of the lungs. “Owing to their peculiar location and a variety of manifested histologic patterns, pleural thymomas may be confused with other neoplasms and may cause diagnostic problems clinically, radiologically, and morphologically,” the researchers explained. &lt;br /&gt;&lt;br /&gt;In their case report, Monaco and his co-authors highlighted several instances of lesions that need to be examined more closely by physicians during differential diagnosis in order to distinguish primary pleural thymoma from other neoplasms, especially malignant mesotheliomas, as in their case study. In rare instances, according to the authors, malignant mesotheliomas may have a significant infiltration of the lymphoid, thus giving rise to diagnostic mistakes. In addition, they pointed out that close similarities may exist between thymic tumors and malignant mesothelioma in small biopsies, thus making analysis problematic. “An awareness of these interpretative pitfalls is important to prevent misdiagnosis of malignant pleural mesothelioma,” they cautioned. &lt;br /&gt; &lt;br /&gt;“Because of their ectopic site and variety of histologic patterns, as well as the occurrence of an ‘invasive’ border, diagnosis of primary pleural thymomas via pleural biopsy can be very difficult, especially if the pathologist is not aware of this entity or if the typical features of thymoma are lacking,” the researchers said. Owing to the possibility of thymomas mimicking both radiological and microscopical lesions, Monaco and fellow authors stressed upon the consideration of a primary pleural thymoma in the diagnostic approach concerning pleural pathology. Their diagnosis of pleural thymoma in their patient, outlined in their case report, was established based on careful examination of histological features, combined with radiographic, and surgical findings — which they argued “should be considered essential for excluding any mediastinal involvement.” Hence, “[a] combination of clinical information, histopathologic appearance of the tumor, and immunohistochemical studies will often help to distinguish primary pleural thymoma from other neoplasms,” they concluded.&lt;/p&gt;