Follicular Dendritic Cell Sarcoma

Follicular Dendritic Cell Sarcoma Follicular Dendritic Cell Sarcoma and its paraneoplastic manifestations: Review Abstract:  Follicular Dendritic Cell Sarcoma (FDCS) is a rare neoplasm arising from dendritic cells. The paraneoplastic phenomena are an underreported aspect of FDCS. Here we present a case report of FDCS presenting with autoimmune haemolytic anaemia and have done a detailed review of all its paraneoplastic manifestations. Follicular Dendritic Cell Sarcoma (FDCS) is a rare malignancy, which arises from the follicular dendritic cells. It was first described by Monda et al who describes a series of 4 cases(1). Being a relatively new entity, its classification remains a subject of controversy. It has been variously described as lymphoma, sarcoma and histiocytic neoplasm. It has been grouped under histiocytic and dendritic cell neoplasms by the WHO 2008 classification(2) There is considerable under-reporting of this[G1] entity as it usually presents with unremarkable clinical and radiological features. It is not uncommon to misdiagnose these cases as lymphoma due to many similarities in the morphological features between the two entities. With the emergence of modern immunohistochemistry, the dendritic cell lineage can be confirmed and therefore, there is increasing recognition of this group of disorders. Since the first description in 1986, nearly 350 cases of FDCS have been reported(3) including 11 cases from our country(4) FDCS generally presents as a slow growing, well circumscribed painless mass with a median size of 5 cm(2).   Constitutional symptoms are not usually seen at presentation.   Young to middle-aged adults are affected, without any sex predilection. Over fifty percent of the cases are nodal with cervical and axillary lymph nodes being the most common sites(2). The common extranodal sites include tonsils, nasopharynx, palate,entire gastrointestinal tract, pancreas, liver, peritoneum, and lungs.Computerized[G2]Tomography (CT) scan typically shows morphological aspects of an expansive mass with an increasingly inhomogeneous enhancement, directly proportional to lesion size (due to central necrosis, hemorrhage, and cystic changes with a patchy pattern) (5)[G3] Local recurrence in FDCS is more likely than distant metastasis. More than 50% of the cases recur locally after wide local excision while only 25% cases develop distant metastasis.   FDCS is considered as a low-grade malignancy by some while others consider it as an intermediate-grade malignancy[G4](6, 7). Liu et al have proposed [G5]histological criteria for grading the tumor and assessing the risk of recurrence.[G6](8). [G7][G8] Variations in clinical behavior of FDCS are described in the literature.   At one end of the spectrum, FDCS presenting with multifocal abdominal or pelvic mass behaves like an aggressive tumor (13) on the other hand, FDCS of the liver and spleen presents like an inflammatory pseudotumor and usually has a female predominance. (3) Castlemans disease has been found to be associated with FDCS in a few patients(9-11). It has been proposed that the dysplastic changes and FDC proliferation which occur in Castlemans disease may act as the nidus from which FDCS can evolve.(12)Ebstein-Barr Virus has also been described in association with FDCS especially when the liver or spleen is involved.   CD21 expression on the FDC cells has been suggested to be the entry point for EBV in affected cells.(7) FDCS has also been reported to be associated with secondary amyloidosis(13) FDCS mostly arises within lymphoid follicles and has a known association with Castlemans disease. Hence it was postulated that it arises from lymphoid precursors. But studies by Krautler et al suggest that they may arise from prevascular stomal precursor cells, which express platelet-derived growt[G9]h factor beta(14) FDCS has a distinct picture on histopathology a storiform arrangement of spindle-shaped cells with elongated nuclei, delicate, dispersed chromatin and pale eosinophilic cytoplasm. Lymphocytes are seen scattered among the tumor cells and they may also be seen gathered around blood vessels,creating a cuffing pattern. Another characteristic pattern is a concentric whorl.FDCS is specifically immunopositive to CD21, CD35, and/or CD23, vimentin, fascin, HLA-DR, EMA, D2-40, clusterin, and CXCL13. It shows variable positivity to CD68, CD45, CD3, and CD20.[G10](7) a unique point in IHC of FDCS is expression of clusterin which is almost always strongly positive , while in other dendritic cell neoplasms, this marker is weakly positive.(13) Surgical excision of the tumor has been attempted in well circumscribed FDCS. Although some reports suggest that they recur soon afterward(15). Pooled data analysis confirms that surgery remains a good option for localized disease(3, 16). In view of the rarity of FDCS, there is no standard chemotherapeutic regimen for the same. Both lymphoma and sarcoma directed therapies have been tried.   CHOP regimen is one of the commonly used with variable results. [G11][G12]CHOP therapy has been postulated to have an indirect action on FDCS by some authors. It has been postulated that CHOP therapy depletes the B lymphocytes leading to a reduction in the growth factors for FDCS[G13](17). Other regimens which have been tried include ABVD, EPOCH, ICE, and cisplatin/epirubicin(13). Gemcitabine and cisplatin in combination with imatinib(18)and single-agent rituximab[G14]are the other reported regimens with some activity against FDCS(19).[G15][G16] Case Report A 60-year-old female presented with 2 months history of easy fatiguability[G17] and low-grade fever. She was detected to have severe anemia[G18] and mild icterus with difficulty in blood cross matching at a local hospital. She was referred to our institute for further evaluation. General examination revealed marked pallor and generalized lymphadenopathy. The liverwas palpable 5 cm below right costal margin and the spleen was palpable 6 cm below left costal margin. Laboratory evaluation revealed Coombs positive hemolytic anemia, which partially responded to steroid therapy. Her Lymph node excision biopsy showed diffuse effacement of nodal architecture with multiple fascicles of spindle cells traversing the lymph node and wrapping around the pre-existing vessels admixed with many eosinophils and plasma cells (Figure 1a-c). Immunohistochemistry for CD20, CD3, S100, CD 45 and PD-1 were negative, whereas CD23 showed strong membranous positivity in these spindle cells (Figure 1d-i).   Th e histopathological examination was suggestive of Follicular dendritic cell sarcoma. Due to the disseminated involvement by FDCS and associated autoimmune hemolytic anemia, she was treated with CHOP chemotherapy. Both disease and anemia responded to therapy. There are numerous case reports of FDCS presenting with similar paraneoplastic manifestations. They are reviewed below.[G19][G20] Paraneoplastic manifestations of FDCS Paraneoplastic manifestations are a constellation of signs and symptoms that are not directly caused by the malignancy(20). All paraneoplastic manifestations reported with FDCS are of an autoimmune nature. Although they appear similar to classic autoimmune diseases, paraneoplastic autoimmune disorders tend to be more aggressive. Their management too is centered in part on the underlying malignancy (AI) A systematic search was performed on Medline and the paraneoplastic manifestations reported with FDCS in English Literature were identified. (table 1) I. Paraneoplastic Pemphigus (PNP) PNP usually presents secondary to an underlying malignancy, mainly Chronic Lymphocytic leukemia, Non Hodgkins Lymphoma, Thymoma and Castlemans disease(21). PNP is the most commonly reported paraneoplastic manifestation with FDCS. There are 22 cases reports in English literature till date. While axillary and cervical lymphadenopathy is the most common presentation of FDCS, PNP has been reported mostly with retroperitoneal FDCS.   The clinical course of PNP is at variation with the relatively benign course of FDCS and most authors have reported death soon after detection of PNP.   An association with the hyaline vascular variant of [G21]Castlemans disease has been described in 27% of these cases. Reports of other malignancies associated with paraneoplastic syndromes suggest that it is associated with an antitumor response. The underlying malignancy remained undetectable for up to a year after the paraneoplastic syndrome first manifested due to this effect. It has been suggested that the immune response against the paraneoplastic antigen in the tumor, slows down the growth of the tumor(22). The status of FDCS is not in remission in most of the available reports.   Thus, there is no evidence to suggest an antitumor effect in patients presenting with PNP. Resection of the underlying FDCS along with oral steroids for the PNP has been the usual treatment, but there are 2 reports of usage of higher immunosuppression to successfully control the PNP(18, 23). II.Myasthenia Gravis (MG) Seven cases of myasthenia gravis have been reported in literature till date. One case was also reported to be associated with Castlemans disease Interestingly, four of the seven cases also had paraneoplastic pemphigus. A similar presentation has been reported with another malignancy involving the immune system. Thymoma has a well-known association with MG. Less commonly, it has also been reported with PNP and there is even a report of Thymoma presenting with both MG and PNP. The authors have suggested that the linkage is indirect, through a triad, which also includes the tumor rather than a direct relation. [G22][G23][G24][G25] A similar linkage may explain the cases of FDCS with MG and PNP. Alternatively, CD which [G26]has known association with both these conditions could be the missing link[G27](24-26). But among available literature, there was no evidence of CD with FDCS and MG in all but one case.[G28][G29][G30] The treatment has been IV immunoglobulin, pyridostigmine, and steroids. Most of the authors have reported a good response to therapy with no mortality.[G31][G32] This is in resonance with the findings of MG with other disorders. Thymoma associated with MG is found to have a better prognosis than thymoma without MG. This has partly been attributed to earlier detection of the disease(27) III. Autoimmune Hemolytic Anemia AIHA is a well-known phenomenon in lymphoproliferative disorders. Among the solid organ cancers, a majority of the available literature is with Kaposi sarcoma, lung, kidney and colorectal ca[G33]ncers. It may occur prior to, concurrent with cancer or well after the end of [G34]treatment (28). Two different responses to therapy have been documented with paraneoplastic AIHA. Some cases are steroid resistant and respond to treatment of the primary malignancy. While, AIHA present along with metastatic[G35] cancers are usually steroid responsive.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   [G36] A search of the literature revealed that [G37]ours is only the second case of AIHA with FDCS reported. Conry et al. had reported a 36-year-old African-[G38][G39]American[G40] female who had presented with AIHA not responding to steroids or splenectomy. She presented 1 year later with the abdominal lump which was diagnosed as FDCS. She did not respond to radiotherapy alone but had a good response to chemotherapy with gemcitabine and docetax[G41]el(17). Experience in this case and our case may be insufficient to label AIHA as a paraneoplastic manifestation of FDCS, but several plausible mechanisms of occurrence of AIHA exist in patients of FDCS. And FDCS has known association with other autoimmune paraneoplastic syndromes. So with increased awareness of this association, we hope that more such cases will be documented. [G42][G43] Proposed mechanisms for development of autoimmunity[G44] Castlemans disease is known to be associated with PNP. Several authors have suggested that a preexisting Castlemans may be the cause of PNP in cases of FDCS. Maverakis et al divide paraneoplastic autoimmune disorders broadly into 3 categories:   (i) Disruption of central tolerance, (ii) peripheral immune dysregulation and   (iii) alteration of self-antigens[G45](29). The mechanisms proposed for the occurrence of paraneoplastic phenomena in FDCS are so varied that we could find at least one hypothesis under each of these three headings.[G46] Disruption of Central tolerance 1.Hartert et al and Kim et al have reported immature T cell proliferation, which is not characteristic of FDCS, in those presenting with Myasthenia Gravis. The resulting immune dysregulation may be lead to paraneoplastic phenomena (30, 31). 2. Spreading epitope phenomenon states that cytokines produced by the tumor induce immunoglobulin production, which in turn leads to paraneoplastic phenomena(32). [G47] Peripheral immune dysregulation[G48] 1. B7 is a ligand which required for activation of T cells. Most antigen presenting cells have a low expression of B7 ligand, the only exception being the dendritic cell. The B7 expression on NHL cells[G49] has been proposed as the mechanism underlying autoimmune phenomena seen in them(29). FDCS which arises from dendritic cells may also have a similar mechanism. Alteration of self-antigens[G50] 1.Antibodies directed against the tumor may cross-react with epiderm[G51]al antigens in the case of PNP(32). Shared antigens between FDCS and erythrocytes like CD 35 may be the link in case of Autoimmune Hemolytic Anemia Conclusion The paraneoplastic phenomena are an underreported aspect of FDCS. The clinical scenario is not uniform among all FDCS with paraneoplastic phenomena. While PNP is associated with poor prognosis, the available reports on AIHA and MG suggest a relatively benign course. There are only 2 cases of AIHA reported with FDCS. Although the mechanism for the development of AIHA in FDCS has been proposed, there is a possibility that it is simply a [G52]case of 2 unrelated diseases occurring together.   In the times to come, better recognition of this entity amongst pathologists may lead to an identification of a larger number of patients. Thereby our understanding of this rare neoplasm and its even rare[G53][G54]r complication of PNS will improve Table I: Case reports of FDCS with Para Neoplastic Pemphigus No Year Age/Sex Castleman Location of FDCS Therapy given Interval to PNP Status of FDCS when PNP occurred Outcome and comments Ref. 1 1999 66/M + Abdominal Surgery 480 months Post-excision[G55] Died after 8 days (9) 2 2004 64/F Abdominal Surgery 18 months No Alive at 7m (33) 3 2005 32/M + NA Surgery + Chemo NA Not in remission Died at 3m (10) 4 2005 27/F Abdominal NA NA NA NA (34) 5 6 2005 53/F + Abdominal Surgery Simultaneous Not in remission Died at 1 year (35) 7 2008 60/M Lung Nil Simultaneous Post-excision[G56] Died at 6m (19) 8 2008 67/M Abdominal Surgery 1 months Post-excision Relapse at 12m MG+ (36) 9 2010 68/M Abdominal Surgery 1 month Post-excision Died at 24m MG + (31) 10 2011 NA NA NA NA NA Relapsed (11) 11 2011 NA + NA NA NA NA NA (11) 12 2011 NA + NA NA NA NA NA (11) 13 2012 39/F NA Surgery NA NA Alive at 60m (37) 14 2012 67/M NA Surgery Simultaneous Post-excision Died after 21m MG + (37) 15 2012 68/M Abdominal Surgery Simultaneous Post-excision Died at 3m Synchronous thyroid and renal cancer (38) 16 2013 61/F + Abdominal + multiple sites Surgery + Chemo 36 months Not in remission Died (39) 17 2013 28/M + Abdominal Chemo Simultaneous Not in remission NA (40) 18 2013 20/M + Rt pelvis Chemo simultaneous Not in remission Died at 1m (41) 19 2014 46/F Liver Surgery + Chemo 6 months Not in remission Died at 12m (23) 20 2014 20/M Rt parahilar Surgery + Chemo Nil Post-excision Alive at 12m (42) 21 2015 26/F + NA NA NA NA Alive MG+ (43) Case reports of FDCS with Myasthenia Gravis No Year Age/Sex Castleman Location of FDCS Therapy given Interval to MG Status of FDCS when MG occurred Outcome and comments Ref. 1 2008 67/M Abdominal Surgery 1 months Post-excision Relapse at 12 m PNP+ (36) 2 2010 68/M Abdominal Surgery Simultaneous Post-excision Died at 24m PNP+ (31) 3 2010 39/F Mediastinal Surgery 36 months prior to FDCS Not in remission NA (30) 4 2010 72/F + Mediastinal Surgery 7 months prior to FDCS Not in remission Alive at 8m (25) 5 2011 59/F Axillary Surgery 1.5 months Post-excision NA (44) 6 2012 67/M NA Surgery Simultaneous Post-excision Died after 21m PNP+ (37) 7 2015 26/F + NA NA NA NA Alive PNP+ (43) Case reports of FDCS with Auto Immune Hemolytic Anemia No Year Age/Sex Castleman <