Inflammatory pseudotumor-like follicular dendritic cell sarcoma: A brief report of two cases

A rare case of an EBV-positive inflammatory follicular dendritic cell tumor of the spleen

Epstein-Barr virus positive inflammatory pseudotumor follicular dendritic cell sarcoma (EBV+ FDCS) is a rare indolent neoplasm that presents primarily in the spleen and liver. We display a case of EBV+ FDCS in the spleen, its clinic-pathologic properties, and treatment. Our patient was evaluated following an incidental finding of a splenic mass on imaging after a traumatic injury. Computed tomography and magnetic resonance imaging both confirmed a well-circumscribed lesion in the spleen. Consequently, the patient underwent a robotic-assisted diagnostic splenectomy. Histologic examination revealed portions of spleen with partial effacement of tissue architecture by a well-circumscribed nonencapsulated mass displaying atypical, spindled cells-positive for EBER (CISH), EBV LMP1, smooth muscle actin, and clusterin-mixed inflammatory elements, and interspersed small lymphocytes.

EBV-Positive Inflammatory Follicular Dendritic Cell Sarcoma of the Spleen: Report of an Aggressive Form With Molecular Characterization

EBV-positive inflammatory follicular dendritic cell sarcoma (EBV+ inflammatory FDCS) is a rare neoplasm almost exclusively located in the spleen or liver. It is characterized by a proliferation of EBV-positive spindle-shaped cells bearing follicular dendritic cell markers, associated with an abundant lymphoplasmacytic infiltrate. EBV+ inflammatory FDCS is often asymptomatic or responsible for mild symptoms. It usually displays an indolent course and its prognosis is excellent after tumor removal, although relapsing and metastatic forms exist. Herein, we describe an aggressive form of splenic EBV+ inflammatory FDCS in a 79-year-old woman presenting with abdominal pain, deterioration of general health status, major inflammatory syndrome, and symptomatic hypercalcemia. A splenectomy was performed leading to a rapid improvement in her clinical condition and normalization of laboratory abnormalities. Unfortunately, her symptoms and laboratory abnormalities reappeared 4 months later. Computed tomography showed a mass in the splenectomy site and multiple liver and peritoneal nodules. Further analyses were performed on tumor tissue and showed positive phospho-ERK staining of tumoral cells indicating activation of MAPK pathway. Inactivating mutations were found on CDKN2A and NF1 genes. Subsequently, the patient's condition deteriorated rapidly. Since interleukin-6 levels were dramatically increased, tocilizumab was used but only had a transient effect on the patient's symptoms and inflammatory syndrome. Antitumor agent gemcitabine was initiated but her clinical condition continued to deteriorate and the patient died 2 weeks later. The management of aggressive forms of EBV+ inflammatory FDCS remains challenging. However, since these tumors seem to display genetic alterations, better characterization could lead to molecular targeted therapies.

Imaging findings of Epstein-Barr Virus-positive inflammatory follicular dendritic cell sarcoma of spleen: A case report

BACKGROUND

Spleen Epstein-Barr Virus (EBV)-positive inflammatory follicular dendritic cell sarcoma (FDCS) is rare, and the imaging signs are unclear. The COVID-19 has been confirmed to be the cause of pneumonia and can cause a variety of diseases including myocarditis. However, it has not been reported to be the cause of the exacerbation or activation of EBV-positive inflammatory FDCS.

OBJECTIVE

The objective is to extract the imaging features of EBV-positive inflammatory FDCS in the spleen and analyze the reasons for the special features of this case.

METHODS

By analyzing the patient's treatment process and imaging examinations (A 77-year-old female was admitted to the hospital due to generalized discomfort and pain symptoms. When she was admitted to the hospital a year earlier with COVID-19 pneumonia, a chest CT scan showed that she had a splenic tumor. During this admission, CT scans showed two irregularly shaped and unevenly dense soft tissue density masses within the spleen, with uneven enhancement on contrast-enhanced im-aging within the solid components and along the edges. PET/CT scans revealed elevated glucose metabolism in the masses. Postoperative pathological diagnosis confirmed splenic EBV-positive inflammatory FDCS.), reading the literature, sorting out the disease cognitive process, epidemiology, and pathological data of EBV-positive inflammatory FDCS, we discussed the imaging manifestations and possible differential diagnosis of the disease.

RESULTS

The patient was finally diagnosed with splenic EBV-positive inflammatory FDCS.

CONCLUSIONS

Imaging features of EBV-positive inflammatory FDCS in the spleen include a high incidence of hemorrhage and necrosis, persistent moderate enhancement of the solid portion, a "capsular-like enhancement" structure at the tumor edge, and possibly active glucose metabolism with high Standardized Uptake Values (SUVs). COVID-19 infection and long-term COVID-19 sequelae may exacerbate and activate EBV-positive inflammatory FDCS in the spleen, and the mechanism remains to be further studied.

Clinicopathologic profile of intra-abdominal follicular dendritic cell sarcoma: A study of three cases with a literature review

Follicular dendritic cell sarcoma (FDCS) is a rare tumor, which mainly originates from follicular dendritic cells (FDCs) in the lymph nodes. Sometimes FDCS can arise from outside the lymph nodes. FDCS is an extremely rare malignant tumor in intraperitoneal or retroperitoneal tissue. We gathered the detailed clinical data of three patients diagnosed with FDCS in the abdomen. The clinical observations and histopathologic and immunohistochemical features of FDCS were analyzed. The patients included two men and one woman aged 55 ~ 61 years old. The mesentery of the small intestine and colon was involved in case 1, spleen in case 2, and retroperitoneal tissues in case 3. Two patients presented with abdominal masses, and one presented with no obvious symptoms. Histology showed ovoid to spindle neoplastic cells arranged in fascicles and storiforms with inflammatory infiltrate as well as whorled patterns in some areas. Immunohistochemical staining was positive for CD21, CD23, CD35, and SSTR2. FDCS exhibits no characteristic clinical manifestations. Morphologically, FDCS can have overlapping features with many other entities, leading to misdiagnosis. The use of histopathology supplemented with FDC markers, such as CD21, CD23, and CD35, is useful for diagnosis and differential diagnosis.

Case report: Hepatic inflammatory pseudotumor-like follicular dendritic cell sarcoma: a rare case and review of the literature

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is a rare subtype of follicular dendritic cell sarcoma (FDCS) that primarily occurs in the liver and spleen. The etiology of IPT-like FDCS is unknown, and it has nonspecific clinical manifestations, imaging performance and laboratory test results. Recently, a patient with IPT-like FDCS was admitted to our hospital because of abdominal distension and anemia. Over the past 3 years, the patient has been followed up after a liver mass was found in a physical examination. The lesion gradually enlarged and caused compression symptoms. In November 2022, a tumor with a diameter of approximately 20 cm was found in the right posterior lobe of the liver after abdominal enhanced Magnetic resonance imaging (MRI) in our hospital. Liver tumor biopsy before the operation revealed a large number of hyperplastic plasma cells and a small number of spindle cells, and the spindle cells were atypical. After a complete examination, the patient underwent liver resection. Pathology after surgery confirmed liver IPT-like FDCS.

Challenges in the Diagnosis of Epstein-Barr Virus-positive Inflammatory Follicular Dendritic Cell Sarcoma: Extremely Wide Morphologic Spectrum and Immunophenotype

Epstein-Barr virus (EBV)-positive inflammatory follicular dendritic cell (FDC) sarcoma (EBV + IFDCS) is a rare entity, and its histopathological characteristics have not been fully described. Here, we investigated the wide morphologic spectrum and immunophenotype of this tumor with the aim to help avoid misdiagnosis. Thirteen cases of EBV + IFDCS were retrospectively analyzed, combined with a review of 70 cases reported in the literature. The median age of patients was 49 (range, 29 to 67 y). Six patients were male and 7 were female. Most cases (92.3%, 12/13) occurred in the liver or spleen, and only 1 case affected an extra-hepatosplenic site (lung, 7.7%, 1/13). Tumors were assessed for a variety of histologic features and assigned to the following morphologic groups: classic type (53.8%, 7/13), lymphoma-like subtype (38.5%, 5/13), and hemangioma-like subtype (7.7%, 1/13). The classic type had distinct EBV-positive neoplastic cells with a fascicular or storiform growth pattern, variable lymphoplasmacytic infiltrates, and blood vessels. The lymphoma-like subtype had extremely prominent lymphoplasmacytic infiltrates (resembling marginal zone lymphoma with plasmacytoid differentiation) with singly dispersed distinct EBV-positive neoplastic cells, highlighted by in situ hybridization for EBV-encoded small RNA. The hemangioma-like subtype had extremely prominent blood vessels with hyaline and/or fibrinoid degeneration, singly dispersed distinct EBV-positive neoplastic cells, and limited lymphoplasmacytic infiltrates. Immunohistochemically, the neoplastic cells showed variable staining for FDC markers (CD21, CD35, CD23, and SSTR2) and the fibroblastic marker SMA, with the staining ranging from very focal to extensive. The number of EBV-positive neoplastic cells ranged from 80 to 400/HPF. All cases showed variable expression of PD-ligand 1 (PD-L1) (CPS: 5-90). IgG4-positive cells ranged from rare up to 100/HPF. Interestingly, 2 cases satisfied the criteria proposed in a previous study, mimicking IgG4-related disease. EBV + IFDCS is an entity with an extremely wide morphologic spectrum and immunophenotype. Awareness of the spectrum of morphologic presentations of this rare tumor, specifically the lymphoma-like subtype and hemangioma-like subtype, is important for accurate diagnosis.

Inflammatory pseudotumor-like follicular dendritic cell sarcoma with first clinical manifestation of thrombocytopenia: A case report

BACKGROUND

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is often associated with Epstein-Barr (EB) virus infection. The tumor is commonly found in the spleen and liver, and it has been reported in the literature that it can be associated with paraneoplastic pemphigus, myasthenia gravis, and other diseases. A case of IPT-like FDCS with clinical features of thrombocytopenia has not been reported.

PATIENT CONCERNS

A 59-year-old male patient visited our hospital in September 2020 due to bleeding gums and epistaxis.

DIAGNOSIS

Splenic lymphoma with marked thrombocytopenia was initially diagnosed. The patient underwent pathological examination after splenectomy. Microscopic examination showed spindle-shaped or oval cells arranged in loose bundles, a large number of lymphocytes and plasma cells infiltrating the interstitium, and fibrin-like changes in the blood vessel wall. Immunohistochemical detection of tumor cells was positive for CD21, CD35, and Epstein-Barr virus in situ hybridization, and the patient was diagnosed with IPT-like FDCS.

INTERVENTIONS

The patient underwent a splenectomy. The patient received platelet-raising therapy postoperatively.

OUTCOMES

No tumor recurrence or metastasis was found during the 17-month follow-up period, and the platelet count returned to normal.

CONCLUSION

IPT-like FDCS is an uncommon tumor, and its first presentation with marked thrombocytopenia is even rarer. The tumor was clinically and radiographically nonspecific. Definitive diagnosis relies on histopathological and immunohistochemical staining. IPT-like FDCS is biologically indolent and has a favorable prognosis.

Inflammatory pseudotumor-like follicular/fibroblastic dendritic cell sarcoma: focus on immunohistochemical profile and association with Epstein-Barr virus

Inflammatory pseudotumour-like follicular/fibroblastic dendritic cell sarcoma (IPT-like FDCS) is a rare EBV-associated variant of follicular dendritic cell sarcoma, usually arising in the liver or spleen and characterized by a favourable prognosis. The neoplastic cells show variable follicular dendritic cell or fibroblastic reticular cell differentiation and their immunoprofile is still poorly characterized. We describe a case of splenic IPT-like FDCS with unexpected CD31 expression and provide a concise review of English literature on the topic.

Epstein-Barr virus-associated inflammatory pseudotumor variant of follicular dendritic cell sarcoma of the liver: a case report and review of the literature

BACKGROUND

Follicular dendritic cell sarcoma is a rare stromal tumor with no standard treatment. However, some reports have revealed that follicular dendritic cell sarcoma has an inflammatory pseudotumor variant associated with Epstein-Barr virus infection that has a relatively good prognosis. In this report, we present a case of a resected inflammatory pseudotumor variant of follicular dendritic cell sarcoma of the liver, and have reviewed the literature on the clinicopathological, molecular, and genomic features of this tumor.

CASE PRESENTATION

The inflammatory pseudotumor variant of follicular dendritic cell sarcoma originates only in the liver or spleen, causes no symptoms, and is more common in middle-aged Asian women. It has no characteristic imaging features, which partially explains why the inflammatory pseudotumor variant of follicular dendritic cell sarcoma is difficult to diagnose. Pathologically, the inflammatory pseudotumor variant of follicular dendritic cell sarcoma has spindle cells mixed with inflammatory cells and is variably positive for follicular dendritic cell markers (CD21, CD23, and CD35) and Epstein-Barr virus-encoded RNA. On genetic analysis, patients with this tumor high levels of latent membrane protein 1 gene expression and extremely low levels of host C-X-C Chemokine Receptor type 7 gene expression, indicating that the inflammatory pseudotumor variant of follicular dendritic cell sarcoma has a latent Epstein-Barr virus type 2 infection.

CONCLUSIONS

The inflammatory pseudotumor variant of follicular dendritic cell sarcoma is an Epstein-Barr virus-associated tumor and a favorable prognosis by surgical resection, similar to Epstein-Barr virus-associated gastric cancer.

Surgical treatment of liver inflammatory pseudotumor-like follicular dendritic cell sarcoma: A case report

BACKGROUND

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is rare with a low malignant potential. Hepatic IPT-like FDCS has similar clinical features to hepatocellular carcinoma (HCC), making it extremely difficult to distinguish between them in clinical practice. We describe the case of a young female patient diagnosed with HCC before surgery, which was pathologically diagnosed as IPT-like FDCS after the left half of the liver was resected. During 6 mo of follow-up, the patient recovered well with no signs of recurrence or metastasis.

CASE SUMMARY

A 23-year-old female patient with a 2-year history of hepatitis B presented to the Affiliated Hospital of Guizhou Medical University. She was asymptomatic at presentation, and the findings from routine laboratory examinations were normal except for slightly elevated alpha-fetoprotein levels. However, ultrasonography revealed a 3-cm diameter mass in the left hepatic lobe, and abdominal contrast-enhanced computed tomography revealed that the tumor had asymmetrical enhancement during the arterial phase, which declined during the portal venous phase, and had a pseudo-capsule appearance. Based on the findings from clinical assessments and imaging, the patient was diagnosed with HCC, for which she was hospitalized and had undergone laparoscopic left hepatectomy. However, the tumor specimens submitted for pathological analyses revealed IPT-like FDCS. After surgical removal of the tumor, the patient recovered. In addition, the patient continued to recover well during 6 mo of follow-up.

CONCLUSION

Hepatic IPT-like FDCS is difficult to distinguish from HCC. Hepatectomy may provide beneficial outcomes in non-metastatic hepatic IPT-like FDCS.

Case report: Hepatic inflammatory pseudotumor-like follicular dendritic cell sarcoma: A rare case and minireview of the literature

Inflammatory pseudotumor (IPT)-like follicular dendritic cell sarcoma (FDCS) is a rare neoplasm referred to as the FDCS variant. Here we report a 66-year-old female patient suffering from hepatic IPT-like FDCS and summarize IPT-like FDCS reported in the literature. The patient presented with obvious abdominal pain without significant laboratory abnormalities and subsequently underwent surgical resection of a hepatic lesion. Postoperative pathological results demonstrated a vascular tissue-rich neoplasm (7.0-cm maximum diameter). The tumor cells expressed CD21 and CD35, and in situ hybridization detected Epstein–Barr virus-encoded RNA (EBER). Metastasis or recurrence was not detected during the 7-year follow-up.

Imaging and pathological comparison of inflammatory pseudotumor-like follicular dendritic cell sarcoma of the spleen: A case report and literature review

Background

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is a rare subtype of follicular dendritic cell sarcoma (FDCS) that is mainly located in the liver and spleen (1). Splenic IPT-like FDCS is a rare low-grade malignancy with non-specific clinical manifestations and laboratory findings. Herein, we reported the pathological and imaging features of a case with splenic IPT-like FDCS.

Case presentation

A 57-year-old woman was found to have a mass in the spleen during a physical examination and was hospitalized for further treatment. Her laboratory results were within the normal range. Unenhanced and contrast-enhanced computed tomography scans of the whole abdomen showed a round mass in the spleen, with a diameter of about 5 cm. After further examination with enhanced MRI, a provisional diagnosis of splenic hemangioma or splenic hamartoma was made. The patient underwent splenectomy, and the pathological diagnosis was splenic IPT-like FDCS. No tumor recurrence or metastasis was found during the 1-year follow-up after the operation.

Conclusions

Herein, we reported a case of splenic IPT-like FDCS. Although the clinical examination and laboratory examination lack specificity, the imaging of this case showed that the lesion was a solid mass with progressive enhancement, and the central scar showed the characteristics of delayed enhancement, which facilitated the diagnosis.

Granulomatous splenic mass with necrosis revealing an EBV-positive inflammatory follicular dendritic cell sarcoma

Epstein-Barr virus-positive inflammatory follicular dendritic cell sarcoma is a variant of follicular dendritic cell neoplasm most often arising in the liver or spleen. Two histological patterns can be identified in this variant, namely a granulomatous and an eosinophil-rich one. We present the case of a 69-year-old woman with a splenic mass. After being removed, the mass was gray-whitish with an area of necrosis. Histology showed a diffuse distribution of epithelioid granulomas in a background of a dense lymphoplasmacytic infiltrate. Rare atypical cells EBV+ and CD21+ were present in the intergranulomatous areas. Differential diagnosis for the granulomatous type EBV+ inflammatory follicular dendritic cell sarcoma includes infection, sarcoidosis, inflammatory myofibroblastic tumor, T cell lymphoma and vasculitis. The origin of this neoplasm is the follicular dendritic cell, and, due to its similarities with a myofibroblast, differential diagnosis can be challenging. Immunohistochemistry for dendritic markers and in situ hybridization for EBER remain diagnostic keys.

Machine learning analysis for the noninvasive prediction of lymphovascular invasion in gastric cancer using PET/CT and enhanced CT-based radiomics and clinical variables

PURPOSE

Lymphovascular invasion (LVI) is associated with metastasis and poor survival in patients with gastric cancer, yet the noninvasive diagnosis of LVI is difficult. This study aims to develop predictive models using different machine learning (ML) classifiers based on both enhanced CT and PET/CT images and clinical variables for preoperatively predicting lymphovascular invasion (LVI) status of gastric cancer.

METHODS

A total of 101 patients with gastric cancer who underwent surgery were retrospectively recruited, and the LVI status was confirmed by pathological analysis. Patients were randomly divided into a training dataset (n = 76) and a validation dataset (n = 25). By 3D manual segmentation, radiomics features were extracted from the PET and venous phase CT images. Image models, clinical models, and combined models were constructed by selected enhanced CT-based and PET-based radiomics features, clinical factors, and a combination of both, respectively. Three ML classifiers including adaptive boosting (AdaBoost), linear discriminant analysis (LDA), and logistic regression (LR) were used for model development. The performance of these predictive models was evaluated with respect to discrimination, calibration, and clinical usefulness.

RESULTS

Ten radiomics features and eight clinical factors were selected for the development of predictive models. In the validation dataset, the area under curve (AUC) values of clinical models using AdaBoost, LDA, and LR classifiers were 0.742, 0.706, and 0.690, respectively. The image models using AdaBoost, LDA, and LR classifiers achieved an AUC of 0.849, 0.778, and 0.810, respectively. The combined models showed improved performance than the image models and the clinical models, with the AUC values of AdaBoost, LDA, and LR classifier yielding 0.944, 0.929, and 0.921, respectively. The combined models also showed good calibration and clinical usefulness for LVI prediction.

CONCLUSION

ML-based models integrating PET/CT and enhanced CT radiomics features and clinical factors have good discrimination capability, which could serve as a noninvasive, preoperative tool for the prediction of LVI and assist surgical treatment decisions in patients with gastric cancer.

Inflammatory pseudotumor-like follicular dendritic cell sarcoma of the liver

A 53-year-old female with a history of HLA-B27 positive polyarthritis underwent a splenectomy due to an incidental splenic lesion, which was confirmed as an inflammatory pseudotumor (IPT). Afterwards, two liver lesions were found and histopathological examination revealed inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS). The patient received NSAIDs, corticosteroids, antibiotics and azathioprine, with no response. Within the next few months, there was an abrupt clinical worsening due to rapid progression of the hepatic lesions and a massive hepatomegaly. New biopsies were obtained, showing undifferentiated sarcoma. The patient started chemotherapy with doxorubicin and eventually died.

Hepatic inflammatory pseudotumor-like follicular dendritic cell tumor: a case report

Background

Inflammatory pseudotumor-like follicular dendritic cell sarcoma is a rare histological variant of follicular dendritic cell sarcoma involving typically the spleen and the liver, often linked to the presence of Epstein–Barr virus infection. Definite diagnosis of this type of sarcoma is difficult to make owing to nonspecific clinical and imaging findings and is based on histopathological features. Inflammatory pseudotumor-like follicular dendritic cell sarcoma is described as a low-aggressivity tumor with a favorable prognosis.

Case presentation

We report the case of a 34-year-old Caucasian woman, Epstein–Barr virus positive, diagnosed with hepatic inflammatory pseudotumor-like follicular dendritic cell sarcoma and surgically treated in November 2014, who developed 6 years later a recurrence for which she underwent once again surgical treatment. As far as we know, fewer than 30 reports of inflammatory pseudotumor-like follicular dendritic cell liver tumors have been reported in the English literature.

Conclusions

Although it is an uncommon tumor, inflammatory pseudotumor-like sarcoma is a diagnostic worth being taken in consideration, and surveillance is recommended owing to the possibility of recurrence.

Inflammatory pseudotumor-like follicular dendritic cell sarcoma: Literature review of 67 cases

Inflammatory pseudotumor (IPT)-like follicular dendritic cell (FDC) sarcoma is rare. The 2017 World Health Organization classification of tumors of hematopoietic and lymphoid tissues noted that data on its clinical outcome are limited, but that the tumor appears to be indolent. The aim of this study was to summarize the clinical characteristics, treatment outcomes, and prognostic factors for IPT-like FDC sarcoma. A literature review was conducted on retrospective analyses of clinical data and prognostic information on IPT-like FDC sarcoma reported between 2001 and 2020. A total of 67 cases of IPT-like FDC sarcoma were retrieved from the literature, documenting that it occurs predominantly in middle-aged adults, with a marked female predilection. Six patients had a separate malignancy and five had an autoimmune disease. Typically involving the spleen and/or liver, it may also selectively involve the abdomen, gastrointes-tinal tract, pancreas, retroperitoneum, and mesentery. Necrosis, hemorrhage, noncaseating epithelioid granulomas, and fibrinoid deposits in blood vessel walls are often present. The neoplastic cells are predominantly positive for follicular dendritic cell markers such as cluster of differentiation 21 (CD21), CD23, CD35 and CNA.42 and are consistently Epstein-Barr virus (EBV)-positive. Mitoses were very rare in most cases. Most patients were treated by surgery alone. Disease status at the time of last follow-up was known for 57 patients with follow-up time ranging from 2 to 144 mo. Local and/or distant recurrence after initial treatment was seen in 15.8% of the patients. The 1- and 5-year progression-free survival for the entire group was 91.5% and 56.1%, respectively. Kaplan-Meier and multivariate analyses showed that age, sex, tumor size, and pathological features were not risk factors for disease progression. IPT-like FDC sarcoma appears to be mildly aggressive and requires annual surveillance. Surgery is the most effective treatment modality, and the role of adjuvant chemotherapy for postoperative management is unclear. EBV is likely to play an important role in the etiology of IPT-like FDC sarcoma.

Clinicopathological characteristics of extranodal follicular dendritic cell sarcoma: A report of two cases

Follicular dendritic cell sarcoma (FDCS) is an extremely rare tumor, which mainly originates from FDCs in the lymph nodes. Sometimes FDCS can arise from outside the lymph nodes due to the existence of acquired lymphoid tissue, which becomes the histological basis of the tumor. The diagnosis of FDCS, particularly extranodal FDCS, presents a challenge for pathologists and hematopathologists. The present study presents two cases of extranodal FDCS based on clinical features and histomorphology. Soft tissue of the chest wall was involved in case 1 and right tonsil tissue in case 2. Case 1 underwent surgery, and was in good health post-operatively. During the 5-month post-operative follow-up period, the patient was healthy in all respects. Case 2 received surgery combined with radiotherapy, and the follow-up data reported that the patient remained alive, without signs of recurrence or metastasis during the 4-month post-operative follow-up period. Additionally, a total of 102 cases of extranodal FDCS were retrieved from the literature, which were extracted and reviewed carefully. The rates of recurrence, metastasis and mortality were 14.63 (12/82), 17.07 (14/82) and 8.29% (15/82), respectively. The overall survival rates of the 102 cases, showing 2-year total survival rates, were 70%, the same with that of 5-year total survival rates. The 2-year tumor-free total survival rates were 68%, and the 5-year equivalents were 32%. Female patients had a poorer prognosis than male patients (P<0.05). Kaplan-Meier estimation presented no statistically significant differences between disease-free survival rates or overall survival rates and age, tumor size or treatment (P>0.05).

A rare case of primary pulmonary inflammatory pseudotumor-like follicular dendritic cell sarcoma successfully treated by lobectomy

Primary pulmonary inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is extremely rare. Here, we report a case of a 64-year-old female with primary pulmonary IPT-like FDCS. The patient was found to have a solid nodule in the right lower lobe (RLL) of the lung incidentally without any symptoms or signs of discomfort. The chest computed tomography (CT) showed that there was an irregular nodule in the basal segment of the RLL, approximately 2.0 cm × 1.1 cm × 1.0 cm in size, of 15 HU in CT value. While the result of the fiberoptic bronchoscope-guided biopsy of the mass showed that there was inflammatory cell infiltration, no evidence of malignancy was found. After a thorough discussion of the multidisciplinary team, lobectomy of the RLL and systematic lymph node dissection were performed for the patient. Histologic analysis of the resected mass revealed infiltration of a large number of lymphocytes and plasma cells with the expression of CD21, CD23, CD35 were positive. In addition, the Epstein-Barr virus (EBV) probe in situ hybridization were positive. As a result, the diagnosis of EBV-positive IPT-like FDCS was strongly supported. No recurrence or any signs of metastasis were found during a 10-month follow-up time. As we have reported in this rare case, the diagnosis of primary pulmonary IPT-like FDCS should be considered even when there is only lymphoplasmacytic infiltration and no evidence of malignant tumor cells in the lung.

Extranodal Follicular Dendritic Cell Sarcoma-A Review: "What the Mind Does Not Know the Eye Does Not See"

Follicular dendritic cell sarcoma (FDCS) is an intermediate-grade malignancy of follicular dendritic cells, which are derived from mesenchymal stem cells. Nodal FDCS is well-recognized. However, when it occurs at an extranodal site, it may not be recognized and is often misdiagnosed. These tumors exhibit a variable spindle to epithelioid cell morphology with a lymphocytic infiltrate and a distinct immunophenotype. The World Health Organization has classified this entity under tumors of hematopoietic and lymphoid tissue, that is, histiocytic and dendritic cell neoplasms. However, its occurrence at extranodal sites and its behavior and management more closely resemble that of a soft tissue tumor. Increased awareness about the existence of FDCS at extranodal sites may aid in the reduction of diagnostic errors. We wish to draw attention to this entity by reporting our experience of 54 cases of extranodal FDCS encountered over a period of 14 years and present a review of the literature of this underrecognized entity. We also describe the ontogeny and molecular pathogenesis of this uncommon lesion.

Intra-abdominal inflammatory pseudotumor-like follicular dendritic cell sarcoma associated with paraneoplastic pemphigus: A case report and review of the literature

BACKGROUD

Follicular dendritic cell (FDC) sarcomas are rare neoplasms that occur predominantly in the lymph nodes. They can also occur extranodally. Extranodal FDC sarcomas most commonly present as solitary masses. Inflammatory pseudotumor (IPT)-like FDC sarcomas, a subcategory of FDC sarcomas, are rarer than other sarcoma subtypes. They are composed of spindle or ovoid neoplastic cells and exhibit an admixture of plasma cells and prominent lymphoplasmacytic infiltration. Paraneoplastic pemphigus (PNP), also known as paraneoplastic autoimmune multiorgan syndrome, is a rare autoimmune bullous disease that is associated with underlying neoplasms. PNP has a high mortality, and its early diagnosis is usually difficult.

CASE SUMMARY

We describe a 27-year-old woman who presented with stomatitis, conjunctivitis, and skin blisters and erosions as her first symptoms of PNP with an intra-abdominal IPT-like FDC sarcoma. The patient underwent surgical tumor resection and received tapering oral corticosteroid treatment. She showed no recurrence at the 1-year follow-up.

CONCLUSION

IPT-like FDC sarcomas are rare underlying neoplasms that have an uncommon association with PNP. PNP-associated FDC sarcomas predominantly occur in intra-abdominal sites and suggest a poor prognosis. Surgical resection is an essential and effective treatment for PNP and primary and recurrent FDC sarcomas.