Metin Ozdemirli

Clinicopathologic features of post-transplant lymphoproliferative disorders arising after pediatric small bowel transplant

Few studies examined the clinicopathologic features of PTLD arising in pediatric SBT patients. Particularly, the association between ATG and PTLD in this population has not been described. Retrospective review of 81 pediatric patient charts with SBT – isolated or in combination with other organs – showed a PTLD incidence of 11%, occurring more frequently in females (median age of four yr) and with clinically advanced disease. Monomorphic PTLD was the most common histological subtype. There was a significant difference in the use of ATG between patients who developed PTLD and those who did not (p < 0.01); a similar difference was seen with the use of sirolimus (p < 0.001). These results suggested a link between the combination of ATG and sirolimus and development of more clinically and histologically advanced PTLD; however, the risk of ATG by itself was not clear. EBV viral loads were higher in patients with PTLD, and median time between detection of EBV to PTLD diagnosis was three months. However, viral loads at the time of PTLD diagnosis were most often lower than at EBV detection, thereby raising questions on the correlation between decreasing viral genomes and risk of PTLD.

18F‐FDG PET‐CT and trephine biopsy assessment of bone marrow involvement in lymphoma

The ability of positron emission tomography‐computerized tomography (PET‐CT) to accurately detect bone marrow involvement (BMI) has been suggested in Hodgkin lymphoma (HL) and diffuse large B‐cell lymphoma (DLBCL), but its abilities in other histologies is less established. The aim of this retrospective study was to confirm the role of PET‐CT in detecting BMI in DLBCL and HL, and to explore its usefulness in other subtypes. Of the 149 newly diagnosed patients, common subtypes included DLBCL, follicular lymphoma (FL) and HL. In DLBCL, the sensitivity and specificity of PET‐CT at diagnosis were 75% and 92%. In FL, the sensitivity and specificity of PET‐CT were 67% and 85% at diagnosis, and 73% and 89% at relapse. In HL, the sensitivity and specificity were 100% and 74%. PET‐CT was able to detect BMI in patients with negative biopsies. Most of the patients in which PET‐CT failed to identify BMI were already advanced stage by imaging. In this analysis, PET‐CT was highly accurate for detecting BMI at diagnosis in DLBCL and HL and highly specific in FL at diagnosis and relapse. Results also suggested the diagnostic advantage of PET‐CT over bone marrow biopsy in detecting BMI. Prospective evaluation is necessary and may eliminate biopsies in future patients.

EBV‐positive low‐grade marginal zone lymphoma in the breast with massive amyloid deposition arising in a heart transplant patient: A report of an unusual case

According to the 2008 World Health Organization classification, low‐grade lymphomas arising in transplant recipients are not considered as specific types of PTLD. Most such cases are not associated with EBV infections, although rare reports of post‐transplant marginal zone lymphoma have been described. We describe the case of an 18‐yr‐old female with history of heart transplant who developed a breast mass, but was otherwise completely asymptomatic. Surgical excision of the mass and histopathologic examination showed a low‐grade B‐cell lymphoma most consistent with marginal zone lymphoma with massive amyloid deposition; furthermore, numerous tumor cells were positive for EBV by in situ hybridization for EBV‐encoded RNA. The patient was treated with reduction in immunosuppression, and no additional lesions developed. This case describes an atypical presentation of post‐transplant low‐grade B‐cell lymphoma, unusual in its location, histopathologic features, and association with EBV, thereby adding to the rare previous accounts of such an entity, suggesting the need to include post‐transplant marginal zone lymphomas in the current classification of PTLD, and helping in determining the optimal treatment modalities for such tumors.

Myeloid sarcoma with megakaryoblastic differentiation presenting as a breast mass

Myeloid sarcoma is an extramedullary tumor that consists of myeloblasts or immature myeloid cells. The neoplasm can occur in any part of the body, including the bone, periosteum, lymph nodes, skin, and soft tissue and they may occur de novo or in association with acute myeloid leukemia, myeloproliferative neoplasms and myelodysplastic syndromes. Most cases display a myelomonocytic or pure monoblastic morphology. Tumors with megakaryoblastic differentiation are extremely uncommon and may occur in association with transformation of a myeloproliferative disorder. Myeloid sarcoma presenting as a breast mass is very rare and diagnostically challenging. We report a case of myeloid sarcoma with megakaryoblastic differentiation in the breast of a patient with history of essential thrombocythemia. The mass was composed of undifferentiated pleomorphic malignant cells in trabecular cords and nests with many scattered giant malignant cells and brisk abnormal mitoses. On immunohistochemistry, the neoplastic cells were positive for CD61, CD31, CD34, Factor VIII and CD43 which confirmed the diagnosis. To our knowledge, this is the first report of myeloid sarcoma with megakaryoblastic morphology occurring in the breast. Here we discuss the clinicopathologic features of this rare entity and the challenges involved in making this difficult diagnosis.

Synchronous Leydig Cell Tumor and Seminoma in the Ipsilateral Testis

Leydig cell tumor is a rare sex cord tumor that accounts for 1–3% of all testicular neoplasms. Seminomas are more common and occur in 30–40% of testicular tumors. Leydig cell tumors are derived from undifferentiated gonadal mesenchyme and the concurrent development of the tumor and a seminoma which are derived from germinal epithelium in an ipsilateral testis is extremely rare. Here we report a case of ipsilateral Leydig cell tumor and seminoma occurring in a 38-year-old man with a left testicular mass. The key to diagnosis is dependent on histopathology and immunohistochemistry. To our knowledge, this is the first diagnosis of the two disease entities in a unilateral testis using immunohistochemistry. Increased awareness of the entity is important in order to distinguish Leydig cell tumor and seminomas from other malignancies due to difference in therapeutic management.

Intravascular Large B-Cell Lymphoma Mimicking Temporal Arteritis

Intravascular lymphoma is a rare type of lymphoma, characterized by growth of lymphoma cells within the microvasculature. The majority of the cases are of B-cell lineage, although rare examples of T or NK lineage have also been reported. The lymphoma is usually widely disseminated in the vascular spaces of any organ at the time of diagnosis including the skin and bone marrow. Lymph nodes are typically spared. The clinical picture depends on the specific organ involvement making the correct diagnosis very difficult. Here, we report a case of intravascular large B-cell lymphoma diagnosed postmortem on a 69-year-old African-American male who presented with unilateral proptosis and visual loss. An initial diagnosis of temporal arteritis was made and the patient received corticosteroids. However, the patient developed multiorgan failure and expired. On autopsy, there was disseminated intravascular lymphoma involving predominantly vessels within the heart, kidneys, liver, stomach, lungs, adrenal glands, small intestine, bladder, thyroid, and brain. Interestingly, there was also partial involvement of the retroperitoneal lymph nodes which is an unusual presentation in this disorder. Immunohistochemical staining showed that the lymphoma cells were positive for CD20, indicating B-cell phenotype. This case supports the “mimicking nature” of this rare entity with an unusual presentation with proptosis and visual loss, simulating temporal arteritis and a rare involvement of the retroperitoneal lymph nodes. The presentation of intravascular large B-cell lymphoma can vary, and the key to diagnosis is dependent on histopathology and immunohistochemistry. Increased awareness, early tissue diagnosis, and prompt chemotherapy are crucial for this otherwise lethal disease.

Salivary Gland Heterotopia in the Gastroesophageal Junction: A Case Series and Review of the Literature

Heterotopia is defined as the presence of mature, histologically normal, tissue in unusual anatomic sites. When this heterotopic tissue forms a mass, it is called a choristoma. This case series describes 3 cases of gastroesophageal junction (GEJ) salivary heterotopias. While heterotopias are usually incidental findings, choristomas can clinically and endoscopically mimic carcinomas and might lead to unnecessary procedures for the patients. Clinicians should therefore be aware of this entity. Literature search, however, failed to show any reports of salivary gland heterotopias in the GEJ. In fact, literature review revealed only 6 reported cases of salivary gland choristoma in the gastrointestinal tract, none at the GEJ. In this case series, we report 2 cases of salivary gland heterotopia and one case of salivary gland choristoma arising at the GE junction. To our knowledge, this is the first series of its kind in the literature.

Incidental Metastatic Meningioma Presenting as a Large Liver Mass

Meningiomas are slow growing neoplasms of the central nervous system (CNS). Most of the tumors are benign and distant metastasis from a benign meningioma is rare. Metastasis to the liver, although rare, usually presents with hypoglycemia or occurs in conjunction with a clinical history of an intracranial meningioma or following the resection of a prior CNS meningioma, thus making clinical diagnosis relatively easy. Here we present an unusual case of metastatic meningioma to the liver in a 54-year-old female who presented with an incidental liver mass by ultrasound. Her clinical history and physical examination were unremarkable. A partial hepatectomy revealed a meningioma on histology. Further investigation by imaging studies showed a frontal parasagittal dural mass which was confirmed to be a World Health Organization (WHO) grade 1 meningioma. To our knowledge, this is the first report of a clinically silent metastatic meningioma to the liver without either a concurrent or a previous history of meningioma. Precise diagnosis of this challenging case requires high clinical suspicion, histopathology, and immunohistochemistry.

Primary Clear Cell Sarcoma of the Dermis Mimicking Malignant Melanoma

Background: Clear cell sarcoma is a rare malignant soft tissue neoplasm that typically involves tendons and aponeurosis. Clear cell sarcoma in the dermis is an extremely rare occurrence, and it is difficult to differentiate between this neoplasm and dermal malignant melanoma because they have similar morphologic and immunohistochemical features. Although rare, clear cell sarcoma of the skin typically occurs in the extremities. To our knowledge, there are no reported cases of primary clear cell sarcoma of the skin occurring in the neck. Here, we report an unusual case of clear cell sarcoma arising in the skin of the neck. Case Report: A 43-year-old female presented with a right neck lesion. Histologic sections of the lesion showed a nodular proliferation of spindle cells with pale cytoplasm with epithelioid features involving the entire dermis with no epidermal component. The tumour cells were positive for melanocytic markers, including S100 and Human Melanoma Black 45, which led to an initial diagnosis of malignant melanoma. Fluorescence in situ hybridization showed a rearrangement of the EWSR1 gene on chromosome 22q12, which led to a diagnosis of primary clear cell sarcoma in the skin. Conclusion: Because the treatments for clear cell sarcoma and conventional melanoma are different, fluorescence in situ hybridization for EWSR1 should be performed in any dermal lesions with melanocytic features that do not have an in situ component.