Successful treatment of a child having generalized Kaposi's sarcoma after living donor liver transplantation with conversion to sirolimus

Kaposi sarcoma in three pediatric liver transplantation recipients

BACKGROUND

Kaposi sarcoma (KS) is an endothelial cell tumor, rare in children. It is 200 times more frequent after solid organ transplantation than in the general population.

METHODS

We report three cases of pediatric patients who developed KS after liver transplantation (LT).

RESULTS

Case 1, a 4-year-old boy undergoing LT due to familial intrahepatic cholestasis. Five months after LT, he presented with fever, dyspnea, and cough with enlarged lymph nodes and splenomegaly, anemia, thrombocytopenia, elevated liver enzymes, and positive EBV viral load. Lymph node biopsy diagnosed KS with an elevated HHV8 viral load. Case 2, a 4-year-old boy who underwent LT due to secondary biliary cirrhosis resulting from extrahepatic biliary atresia. Two years later, graft dysfunction was noticed with positive EBV viral load, thrombocytopenia, massive cervical lymph node enlargement, and splenomegaly. Lymph node biopsy diagnosed KS, Castleman's disease, and plasmablastic lymphoma related to HHV8 infection. Case 3, a 15-month-old girl, who received two LT due to biliary cirrhosis. Six months later, she presented with diarrhea, abdominal distension, anemia, thrombocytopenia, enlarged lymph nodes, splenomegaly, and positive CMV viral load. Axillary lymph node biopsy diagnosed KS and HHV8 infection was confirmed. In all three cases, tacrolimus was discontinued and, after diagnosis, sirolimus was started. All recovered without relapse and have a good graft function.

CONCLUSIONS

Kaposi sarcoma is a rare disease post-LT in children. Recognizing keywords and early diagnosis is crucial for timely treatment and survival.

Coexistent Kaposi sarcoma and post-transplant lymphoproliferative disorder in the same lymph nodes after pediatric liver transplantation: A case report

BACKGROUND

Kaposi sarcoma and post-transplant lymphoproliferative disorder have been occasionally reported in post-liver transplant patients. However, the simultaneous occurrence of these two diseases in the same lymph nodes is very rare.

CASE SUMMARY

We report the case of a 19-mo-old boy, who presented with intermittent fever and enlarged cervical lymph nodes after liver transplantation. Six cervical lymph nodes were biopsied, and the histopathological examinations revealed multifocal hyperplasia of spindle cells around small blood vessels, extravasated erythrocytes, and heavy infiltration of plasma cells in the cortex and medulla of the lymph nodes. The immunohistochemical analyses of spindle cells revealed positive expression of CD34, CD31, erythroblast transformation-specific-related gene, friend leukemia integration 1, and human herpesvirus-8. The lymphoproliferative lesions expressed CD38, CD138, and multiple myeloma 1. Epstein-Barr encoded RNA in situ hybridization demonstrated Epstein-Barr virus-positive lymphoid cells. Finally, we diagnosed the coexistence of Kaposi sarcoma and post-transplant lymphoproliferative disorder (plasmacytic hyperplasia) in the same lymph nodes. Treatment strategy included anti-CD20 monoclonal antibody (rituximab) and discontinuation of the immunosuppressant therapies. Lymph node biopsies during follow-up examinations revealed lymphoid hyperplasia.

CONCLUSION

The rare coexistence of Kaposi sarcoma and post-transplant lymphoproliferative disorder in the same lymph nodes post-liver transplantation possibly associates with immunodeficiency and Epstein-Barr virus and human herpesvirus-8 coinfection.

mTOR Inhibition and Clinical Transplantation: Liver

The evidence base concerning use of mammalian target of rapamycin (mTOR) inhibitor therapy after liver transplantation is evolving rapidly, clarifying their benefits and disadvantages in different clinical scenarios. The H2304 trial showed that starting everolimus at 1 month posttransplant, with reduced tacrolimus, achieves a sustained improvement in renal function versus standard tacrolimus-based therapy, with at least equivalent immunosuppressive efficacy. Randomized studies evaluating early discontinuation of calcineurin inhibitor (CNI) therapy after introduction of an mTOR inhibitor consistently demonstrated a substantial improvement in renal function versus standard CNI therapy. However, concomitant mycophenolic acid is advisable to avoid an increase in mild biopsy-proven acute rejection, and induction with an interleukin-2 receptor antagonist may also be helpful. High-quality robust data regarding prevention of posttransplant malignancies under mTOR inhibitors is lacking in liver transplantation, although there are some indications of benefit. In maintenance patients, robust data are limited regarding mTOR inhibitor initiation in response to deteriorating renal function or other indications but late conversion (>1 year) appears ineffective. Rates of mTOR inhibitor discontinuation due to adverse events are high, affecting at least a quarter of patients. In conclusion, the evidence base for use of mTOR inhibitors early posttransplant to support CNI reduction now convincingly demonstrates a renal advantage, but adequate adjunctive immunosuppression is essential to preserve efficacy.

Kaposi Sarcoma of Childhood: Inborn or Acquired Immunodeficiency to Oncogenic HHV-8

Kaposi sarcoma (KS) is an endothelial malignancy caused by human herpes virus-8 (HHV-8) infection. The epidemic and iatrogenic forms of childhood KS result from a profound and acquired T cell deficiency. Recent studies have shown that classic KS of childhood can result from rare single-gene inborn errors of immunity, with mutations in WAS, IFNGR1, STIM1, and TNFRSF4. The pathogenesis of the endemic form of childhood KS has remained elusive. We review childhood KS pathogenesis and its relationship to inherited and acquired immunodeficiency to oncogenic HHV-8.

A Review of Human Herpesvirus 8, the Kaposi's Sarcoma-Associated Herpesvirus, in the Pediatric Population

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma (KS)-associated herpesvirus, is the etiologic agent responsible for all types of KS. Although the majority of pediatric KS cases occur in sub-Saharan Africa, a rise in pediatric transplant KS has been reported in developed countries. In addition, HHV-8 is increasingly described as an infectious cause of hemophagocytic lymphohistiocytosis in children. Transmission of HHV-8 among children is poorly understood; however, the literature strongly suggests that horizontal transmission plays a critical role. Acute infection with HHV-8 and progression to KS in children may be different than in adults, and diagnosis may be overlooked. Currently, neither adult nor pediatric treatment guidelines exist. This review provides an overview of HHV-8 disease in children as it relates to epidemic KS, transplant KS, and other disease manifestations. The current state of the literature is reviewed and knowledge gaps are identified for future exploration.

Phosphatase and tensin homolog on chromosome 10 is phosphorylated in primary effusion lymphoma and Kaposi's sarcoma

Primary effusion lymphoma (PEL) is a non-Hodgkin's B-cell lymphoma driven by Kaposi's sarcoma-associated herpesvirus. It is uniquely sensitive to mTOR, PI3K, and Akt inhibitors; however, the basis of this requirement for the mTOR pathway remains to be elucidated. The phosphatase and tensin homolog gene (PTEN) on chromosome 10 controls the first step in the phosphatidylinositol 3 kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway and is genetically inactivated in many solid tumors. We find an absence of PTEN deletions, mutations, or protein mislocalization in PEL. However, we find consistent hyperphosphorylation at serine 380 of PTEN, which is an inactivating modification, in PEL cell lines and in tumor xenografts. We also evaluated a large tissue microarray of Kaposi's sarcoma biopsies and observed concordant high levels of phospho-PTEN, phospho-Akt, and phospho-S6 ribosomal protein. Reintroduction of PTEN into PEL inhibited colony formation in soft agar, verifying the functional dependence of PEL on PI3K signaling. This was also true for PEL cell lines that carried mutant p53 and for KS-like cell lines. Activating PTEN in these cancers may yield a new treatment strategy for PEL, KS, and similar PTEN wild-type lymphomas.

Human herpes virus type 8-associated Kaposi sarcoma in a pediatric liver transplant recipient

  Development of KS in pediatric liver transplant recipients is a rare entity and has dismal prognosis. Latent HHV-8 infection, immunosuppression, and genetic predisposition are possible etiological factors. Decreasing the dose or cessation of immunosuppressive drugs, switching to sirolimus with antiproliferative and antitumor properties, and different chemotherapeutic regimens are the current therapeutic strategies. We herein report a pediatric liver transplant recipient who developed generalized KS at post-transplant fifth month. The disease had an aggressive course despite the highly toxic chemotherapy. On the other hand, a prompt and durable response was provided by paclitaxel with tolerable side effects. The patient is now free of disease for at least 24 months and healthy with good graft function under sirolimus therapy as maintenance immunosuppression. Instead of highly toxic chemotherapy, paclitaxel can be used as therapeutic option in cases with generalized disease and in those who are unresponsive to conventional chemotherapy. However, new studies are needed to assess the efficacy of the paclitaxel therapy in KS in the liver transplant recipients.

HHV-8-related visceral Kaposi's sarcoma following allogeneic HSCT: report of a pediatric case and literature review

An HHV-8-related visceral KS was diagnosed in a 10-yr-old boy after partially matched allogeneic HSCT. This complication occurred 463 days after HSCT and involved tonsils, lymph nodes, hard palate, lung, skin, and paranasal sinuses. Treatment with pegylated liposomal doxorubicin induced long-term remission (33 months) of this disease. HHV-8 infection is quite frequent after HSCT, but KS, and especially its visceral form, is a very rare complication, and its association with HHV-8 has been documented even less frequently. However, our observation suggests that HHV-8-related KS should be taken into consideration in the differential diagnosis of late post-HSCT complications.