Imaging Features of Pulmonary Kaposi Sarcoma–Associated Immune Reconstitution Syndrome

Human Oncoviruses and Thoracic Tumors: Understanding the Imaging Findings

Approximately 1.4 million virus-induced cancers occur annually, representing roughly 10% of the cancer burden worldwide. Seven oncogenic DNA and RNA viruses (ie, oncoviruses) are implicated in approximately 12%-25% of all human cancers owing to a variety of mechanisms as uncommon consequences of the normal viral life cycle. These seven well-recognized human oncoviruses are Epstein-Barr virus (EBV), human T-lymphotropic virus 1, hepatitis B virus, hepatitis C virus, HIV, human papilloma virus (HPV), and human herpesvirus 8 (HHV-8). Several viruses-namely, EBV, HPV, and Kaposi sarcoma herpesvirus or HHV-8-are increasingly being recognized as being related to HIV and/or AIDS, the growing number of transplant cases, and the use of immunosuppressive therapies. Infectious and inflammatory processes, and the accompanying lymphadenopathy, are great mimickers of human oncovirus-related tumors. Although it is often difficult to differentiate these entities, the associated clinical setting and radiologic findings may provide clues for an accurate diagnosis and appropriate management. Malignant lymphoid lesions are best evaluated with multidetector chest CT. The radiologic findings of these lesions are often nonspecific and are best interpreted in correlation with clinical data and histopathologic findings. ^©RSNA, 2022.

CT Halo sign: A systematic review

PURPOSE

The CT Halo sign or Halo sign (HS) refers to ground-glass opacity surrounding a nodule or mass in the lung parenchyma. We conducted a systematic review to find the etiological associations of HS. We also evaluated the diagnostic performances of HS for invasive fungal infections (IFI) in immunosuppressed patients.

METHOD

The systematic review was conducted as per PRISMA guidelines. We searched the PubMed and EMBASE database till June 2018 without any restrictions. Only case reports, case series and original articles published in English language were included. A database created from the electronic searches was compiled and subsequent analysis was done. [PROSPERO registration: CRD42018094739] RESULTS: 168 studies were eligible, which included 51 case reports, 15 prospective studies, 102 retrospective studies. A total of 1977 patients (out of 6371) with HS were identified with age range between <1year-94years. The most common diagnosis in the immunosuppressed, mixed, immunocompetent and not specified groups were IFI (86.9 %, n = 1194), Cryptococcosis (51.6 %, n = 124), Cryptococcosis (40 %, n = 20) and lung neoplasms (81.8 %, n = 36) respectively. 14 studies (11 retrospective, 3 prospective) were included in quantitative analysis. The pooled sensitivity(sn), specificity(sp) and odd's ratio (OR) of HS for diagnosing IFI were 50.4 %, 91 % and 6.61 respectively. Also, HS could not reliably differentiate IPA from mucormycosis in the pooled analysis.

CONCLUSIONS

HS can be seen in a large number of diverse conditions both in immunosuppressed and immunocompetent population. In immunosuppressed patients HS is specific for IFI but cannot rule it out. Additionally, it cannot reliably distinguish between IPA and mucormycosis.

Approach to Peribronchovascular Disease on CT

Diseases that are predominantly peribronchovascular in distribution on computed tomography by definition involve the bronchi, adjacent vasculature, and associated lymphatics involving the central or axial lung interstitium. An understanding of diseases that can present with focal peribronchovascular findings is useful for establishing diagnoses and guiding patient management. This review will cover clinical and imaging features that may assist in differentiating amongst the various causes of primarily peribronchovascular disease.

HIV-related Malignancies and Mimics: Imaging Findings and Management

The risk of developing malignancy is higher in patients with human immunodeficiency virus (HIV) infection than in non-HIV-infected patients. Several factors including immunosuppression, viral coinfection, and high-risk lifestyle choices lead to higher rates of cancer in the HIV-infected population. A subset of HIV-related malignancies are considered to be acquired immunodeficiency syndrome (AIDS)-defining malignancies, as their presence confirms the diagnosis of AIDS in an HIV-infected patient. The introduction of highly active antiretroviral therapy (HAART) has led to a significant drop in the rate of AIDS-defining malignancies, including Kaposi sarcoma, non-Hodgkin lymphoma, and invasive cervical carcinoma. However, non-AIDS-defining malignancies (eg, Hodgkin lymphoma, lung cancer, hepatocellular carcinoma, and head and neck cancers) now account for an increasing number of cancer cases diagnosed in HIV-infected patients. Although the number has decreased, AIDS-defining malignancies account for 15%-19% of all deaths in HIV-infected patients in the post-HAART era. Most HIV-related malignancies in HIV-infected patients manifest at an earlier age with a more aggressive course than that of non-HIV-related malignancies. Understanding common HIV-related malignancies and their specific imaging features is crucial for making an accurate and early diagnosis, which impacts management. Owing to the weakened immune system of HIV-infected patients, other entities such as various infections, particularly opportunistic infections, are prevalent in these patients. These processes can have confounding clinical and imaging manifestations that mimic malignancy. This article reviews the most common AIDS-defining and non-AIDS-defining malignancies, the role of imaging in their diagnosis, and the imaging mimics of malignancies in HIV-infected patients. ^©RSNA, 2018.

Pleuropulmonary Kaposi Sarcoma in the Setting of Immune Reactivation

We present a case of a 26 year with history of HIV/AIDS who presented with a pleural effusion. Serial radiography, pleural fluid analysis as well as clinical symptoms revealed development of Kaposi Sarcoma related immune reconstitution inflammatory syndrome (KS-IRIS) in the setting of initiation of effective anti- retroviral therapy.

Pulmonary Kaposi's Sarcoma and Its Complications in the HAART Era: A Contemporary Case-Based Review

The early years of the acquired immunodeficiency syndrome (AIDS) epidemic introduced the global medical community to Kaposi's sarcoma (KS), a heretofore seldom encountered angiosarcomatous neoplasm associated with human herpesvirus-8. At that time, clinicians treating these KS patients were routinely exposed to the pulmonary manifestations of this malignancy, including characteristic airway lesions, peribronchovascular opacities, and the typically hemorrhagic pleural effusions. They also witnessed uncommon complications of pulmonary KS such as chylous effusions, diffuse alveolar hemorrhage, and immune reconstitution inflammatory syndrome. Since the advent of highly active antiretroviral therapy, the incidence of KS has steadily declined and with that so has clinician familiarity with this disease. Herein, we present four KS cases recently encountered at our institution that illustrate both typical manifestations of pulmonary KS as well as its thoracic complications. The case descriptions are followed by a review of these clinical entities with the aim of restoring awareness among frontline physicians of what is now a rare but not quite extinct AIDS-defining neoplasm.

Case Report: Pulmonary Kaposi Sarcoma in a non-HIV patient

Kaposi Sarcoma (KS) is an angioproliferative tumor associated with human herpes virus 8 (HHV-8).  Often known as one of the acquired immunodeficiency syndrome (AIDS)-defining skin diseases, pulmonary involvement in KS has only been discussed in a handful of case reports, rarely in a non-HIV patient. Herein we report the case of a 77 year-old- male who presented with a 6-week history of progressive dyspnea on exertion accompanied by productive cough of yellow sputum and intermittent hemoptysis. His past medical history was significant for Non-Hodgkin's Follicular B-Cell Lymphoma (NHL). Patient also had biopsy-confirmed cutaneous KS. His physical exam was notable for a 2cm firm, non-tender, mobile right submandibular lymph node.  Lungs were clear to auscultation. He had multiple violet non-tender skin lesions localized to the lower extremities. CT scan of the chest showed numerous nodular opacities and small pleural effusions in both lungs. A thoracenthesis was performed, showing sero-sanguineous exudative effusions. Histopathology failed to demonstrate malignant cells or lymphoma. A subsequent bronchoscopy revealed diffusely hyperemic, swollen mucosa of the lower airways with mucopurulent secretions. Bronchoalveolar lavage PCR for HHV-8 showed 5800 DNA copies/mL.  It was believed that his pulmonary symptoms were likely due to disseminated KS.  This case illustrates the potential for significant lung injury from KS. It also demonstrates the use of PCR for HHV-8 to diagnose KS in a bronchoalveolar lavage sample in a case when bronchoscopic biopsy was not safe. Furthermore, this case is unique in that the patient did not match the typical KS subgroups as HIV infection and other immune disorders were ruled out. Recognition of this syndrome is critical to the institution of appropriate therapy. As such, this case should be of interest to a broad readership across internal medicine including the specialties of Pulmonology and Critical Care.

Classic Kaposi Sarcoma: to treat or not to treat?

Background

Classic Kaposi Sarcoma (KS) is vascular sarcoma, known to be more common in Mediterranean elderly men and characterized by an indolent clinical behavior. To our knowledge, this is the first evidence in literature, describing a spontaneous partial regression in a non-HIV, non-iatrogenic KS.

Case presentation

A 68-years old woman, presenting with weight loss and respiratory symptoms, was diagnosed with a classic KS involving lungs and mediastinal lymph nodes. No skin or mucosal lesions were identified, HIV positivity was ruled out. Due to patient’s choice, she was kept under surveillance with 3-monthly thorax-abdomen-pelvis computed tomography scan (TAP CT). A first reassessment proved progressive disease (PD) associated with symptoms worsening. A new TAP CT, performed at 5 months from the diagnosis, showed stable disease (SD), with a minor reduction in size of mediastinal lymphadenopathies. A further reassessment, performed 5 months later, resulted in a partial response (PR) despite the absence of any medical treatment. Up to date, the disease is in remission, patient is asymptomatic and still on surveillance.

Conclusion

Given the possible indolent behaviour of KS, we believe that close surveillance can represent a valuable approach in selected cases.

Noninfectious pulmonary complications of human immunodeficiency virus infection

Human immunodeficiency virus type 1 (HIV-1) is the retrovirus responsible for the development of AIDS. Its profound impact on the immune system leaves the host vulnerable to a wide range of opportunistic infections not seen in individuals with a competent immune system. Pulmonary infections dominated the presentations in the early years of the epidemic, and infectious and noninfectious lung diseases remain the leading causes of morbidity and mortality in persons living with HIV despite the development of effective antiretroviral therapy. In addition to the long known immunosuppression and infection risks, it is becoming increasingly recognized that HIV promotes the risk of noninfectious pulmonary diseases through a number of different mechanisms, including direct tissue toxicity by HIV-related viral proteins and the secondary effects of coinfections. Diseases of the airways, lung parenchyma and the pulmonary vasculature, as well as pulmonary malignancies, are either more frequent in persons living with HIV or have atypical presentations. As the pulmonary infectious complications of HIV are generally well known and have been reviewed extensively, this review will focus on the breadth of noninfectious pulmonary diseases that occur in HIV-infected individuals as these may be more difficult to recognize by general medical physicians and subspecialists caring for this large and uniquely vulnerable population.

Eponyms in cardiothoracic radiology: Part I. Neoplasms

Eponyms serve the purpose of honoring individuals who have made important observations and discoveries. As with other fields of medicine, eponyms are frequently encountered in radiology, particularly in chest radiology. However, inappropriate use of an eponym may lead to potentially dangerous miscommunication. Moreover, an eponym may honor the incorrect person or a person who falls into disrepute. Despite their limitations, eponyms are still widespread in medical literature. Furthermore, in some circumstances, more than one individual may have contributed to the description or discovery of a particular anatomical structure or disease, whereas in others, an eponym may have been incorrectly applied initially and propagated for years in medical literature. Nevertheless, radiologic eponyms are a means of honoring those who have made lasting contributions to the field of radiology, and familiarity with these eponyms is critical for proper reporting and accurate communication. In addition, the acquisition of some historical knowledge about those whose names are associated with various structures or pathologic conditions conveys a sense of humanity in the field of medicine. In this article, the first of a multipart series, the authors discuss a number of chest radiology eponyms as they relate to neoplasms, including relevant clinical and imaging features, as well biographic information of the respective eponym׳s namesake.

What a differential a virus makes: a practical approach to thoracic imaging findings in the context of HIV infection--part 2, extrapulmonary findings, chronic lung disease, and immune reconstitution syndrome

OBJECTIVE

The Centers for Disease Control and Prevention reported more than one million people with HIV infection in the United States in 2006, an increase of 11% over 3 years. Worldwide, nearly 34 million people are infected with HIV. Pulmonary disease accounts for 30-40% of acute hospitalizations of HIV-seropositive patients, underscoring the importance of understanding the range of cardiothoracic imaging findings associated with HIV infection. This article will cover extrapulmonary thoracic diseases, chronic lung diseases, and immune reconstitution inflammatory syndrome in HIV-infected patients. Our approach is focused on the radiologist's perspective by recognizing and categorizing key imaging findings to generate a differential diagnosis. The differential diagnosis can be further refined by incorporating clinical data, such as patient demographics, CD4 count, and presenting symptoms. In addition, with prolonged survival of HIV-infected patients in the era of highly active antiretroviral therapy, radiologists can also benefit from awareness of imaging features of a myriad of chronic cardiopulmonary diseases in this patient population. Finally, the change of imaging findings and clinical status in response to treatment provides important diagnostic information, such as in immune reconstitution syndrome.

CONCLUSION

Developing a practical approach to key cardiothoracic imaging findings in HIV-infected patients will aid the radiologist in generating a clinically relevant differential diagnosis and interpretation, thereby improving patient care.

[Pulmonary involvement due to HHV-8 virus during the course of HIV infection]

HHV-8 is a herpes virus discovered in 1994 in Kaposi sarcoma cells. Its involvement was later demonstrated in multicentric Castleman disease and in primary lymphoma effusion lymphoma. These diseases arise almost exclusively in immunocompromised patients, mostly in association with HIV infection. Apart from Kaposi's sarcoma, combined antiretroviral therapy does not seem to have reduced the incidence of these diseases, which remain rare. In these three diseases, pulmonary involvement is common and may be the presenting feature. Kaposi's sarcoma of the lung is usually asymptomatic but may require specific therapy. Pulmonary involvement is mostly associated with cutaneous disease. Patients with Castleman disease typically present with fever and lymphadenopathy, associated with interstitial lung disease without opportunistic infection. Patients with primary lymphoma effusion presents with fever and an exudative lymphocytic pleural effusion, without a pleural mass on the CT-scan. Rapid diagnosis of these conditions avoids unnecessary invasive examinations and leads to prompt specific treatment.

Kaposi's sarcoma: imaging overview

Kaposi's sarcoma (KS), a low-grade malignancy that is associated with human herpesvirus-8 (HHV-8), is a multifocal tumor that most commonly affects mucocutaneous sites. It might also involve lymph nodes and visceral organs, in particular of the respiratory and gastrointestinal tract, but it can affect every organ system. Four forms of the disease have been recognized: the classic, the endemic, the transplant-associated, and the epidemic form. The endemic form, or African KS, currently accounts for 10%-50% of all cancers in adults and up to 25% of cancers in children in certain parts of Africa. The epidemic form or acquired immune deficiency syndrome (AIDS)-associated KS is a frequent neoplasm in bisexual and homosexual men with AIDS in the United States. Even though in North America and Europe the incidence of KS in men with AIDS has decreased significantly after the introduction of highly active antiretroviral therapy (HAART), in some developing countries, the incidence of KS keeps growing. The pathophysiology, clinical manifestations, imaging findings, and more relevant differential diagnoses are reviewed.

The diagnostic value of halo and reversed halo signs for invasive mold infections in compromised hosts

The halo sign is a CT finding of ground-glass opacity surrounding a pulmonary nodule or mass. The reversed halo sign is a focal rounded area of ground-glass opacity surrounded by a crescent or complete ring of consolidation. In severely immunocompromised patients, these signs are highly suggestive of early infection by an angioinvasive fungus. The halo sign and reversed halo sign are most commonly associated with invasive pulmonary aspergillosis and pulmonary mucormycosis, respectively. Many other infections and noninfectious conditions, such as neoplastic and inflammatory processes, may also manifest with pulmonary nodules associated with either sign. Although nonspecific, both signs can be useful for preemptive initiation of antifungal therapy in the appropriate clinical setting. This review aims to evaluate the diagnostic value of the halo sign and reversed halo sign in immunocompromised hosts and describes the wide spectrum of diseases associated with them.

Pulmonary manifestations of the immune reconstitution inflammatory syndrome

PURPOSE OF REVIEW

Immune reconstitution inflammatory syndrome (IRIS) is a common occurrence in HIV patients starting antiretroviral therapy (ART), and pulmonary involvement is an important feature of tuberculosis-IRIS and pneumocystis-IRIS. Pulmonologists need an awareness of the timing, presentation and treatment of pulmonary IRIS.

RECENT FINDINGS

Case definitions for tuberculosis-IRIS and cryptococcal-IRIS have been published by the International Network for the Study of HIV-associated IRIS (INSHI). A number of studies have addressed validation of clinical case definitions and the optimal time to commence ART after diagnosis of an opportunistic infection in HIV patients. The pathogenesis of IRIS is being assessed at a molecular level, increasing our understanding of mechanisms and possible targets for future preventive and therapeutic strategies.

SUMMARY

Tuberculosis-IRIS, nontuberculosis mycobacterial-IRIS and pneumocystis-IRIS occur within days to weeks of starting ART, causing substantial morbidity, but low mortality. Cryptococcal-IRIS usually occurs later in the course of ART, and may be associated with appreciable mortality. Early recognition of unmasking and paradoxical IRIS affecting the lung allows timely initiation of antimicrobial and/or immunomodulatory therapies.

Imaging lung manifestations of HIV/AIDS

Advances in our understanding of human immunodeficiency virus (HIV) infection have led to improved care and incremental increases in survival. However, the pulmonary manifestations of HIV/acquired immunodeficiency syndrome (AIDS) remain a major cause of morbidity and mortality. Respiratory complaints are not infrequent in patients who are HIV positive. The great majority of lung complications of HIV/AIDS are of infectious etiology but neoplasm, interstitial pneumonias, Kaposi sarcoma and lymphomas add significantly to patient morbidity and mortality. Imaging plays a vital role in the diagnosis and management of lung of complications associated with HIV. Accurate diagnosis is based on an understanding of the pathogenesis of the processes involved and their imaging findings. Imaging also plays an important role in selection of the most appropriate site for tissue sampling, staging of disease and follow-ups. We present images of lung manifestations of HIV/AIDS, describing the salient features and the differential diagnosis.

Immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) must be considered in the differential diagnosis for any patient infected with HIV who has begun ART in the preceding months. Distinguishing between manifestations of IRIS and active infection is of paramount importance and poses a diagnostic challenge to the provider in the acute care setting. Presentations of IRIS are often atypical for the precipitating pathogen, and novel presentations are likely. Of the diseases associated with IRIS, mycobacteria and cryptococcal infections are commonly encountered, as are dermatologic symptoms in general. The most clinically significant complications of IRIS are those involving the central nervous system, lungs, and eye, and in many of these scenarios systemic steroids may be of benefit. Management should rarely include interruption of ART, except possibly in severe, life-threatening complications.

Pulmonary complications of immune reconstitution inflammatory syndromes in HIV-infected patients

Immune reconstitution inflammatory syndrome (IRIS) describes a paradoxical worsening of clinical status related to recovery of the immune system, as can occur after the initiation of highly active antiretroviral therapy (HAART) in HIV-infected patients. Most commonly, IRIS results from opportunistic infections that can unmask or develop paradoxical worsening following HAART. Cancers, autoimmune conditions and sarcoidosis have also been associated with IRIS. Pulmonary complications may be frequently encountered. This article reviews the types and clinical presentation of IRIS, with a focus on the pulmonary manifestations. Management and outcome of IRIS are considered.

[Human immunodeficiency virus and AIDS-associated immune reconstitution syndrome. State of the art]

Since the arrival of highly active antiretroviral therapy (HAART), immune reconstitution syndrome (IRS) has become an increasingly more frequent complication in patients with human immunodeficiency virus (HIV) infection. This article presents a review of the available evidence on this subject, indexed in MEDLINE-PUBMED, BVS-BIREME, and BioMed Central. The review covers the definition, epidemiology, classification, and diagnostic criteria related to IRS. In addition, the clinical particularities of the most frequent etiologies are described, and a proposal for a therapeutic approach is formulated. The prognosis and future implications of this syndrome in the epidemiology of some infectious illnesses in the HIV-positive population are included. Several unresolved aspects are mentioned, such as those related to the pathophysiology of the condition, use of biomarkers for the diagnosis, and the need for evidence-based therapeutic algorithms to enable standardization of treatment for these patients.

Pulmonary involvement in Kaposi sarcoma: correlation between imaging and pathology

Kaposi sarcoma is a low-grade mesenchymal tumor involving blood and lymphatic vessels. There are four variants of this disease, each presenting a different clinical manifestation: classic or sporadic, African or endemic, organ transplant-related or iatrogenic, and AIDS-related or epidemic. Kaposi sarcoma is the most common tumor among patients with HIV infection, occurring predominantly in homosexual or bisexual men. The pulmonary involvement in Kaposi sarcoma occurs commonly in critically immunosupressed patients who commonly have had preceding mucocutaneous or digestive involvement.

The etiology of Kaposi sarcoma is not precisely established; genetic, hormonal, and immune factors, as well as infectious agents, have all been implicated. There is evidence from epidemiologic, serologic, and molecular studies that Kaposi sarcoma is associated with human herpes virus type 8 infection. The disease starts as a reactive polyclonal angioproliferative response towards this virus, in which polyclonal cells change to form oligoclonal cell populations that expand and undergo malignant transformation.

The diagnosis of pulmonary involvement in Kaposi sarcoma usually can be made by a combination of clinical, radiographic, and laboratory findings, together with the results of bronchoscopy and transbronchial biopsy. Chest high-resolution computed tomography scans commonly reveal peribronchovascular and interlobular septal thickening, bilateral and symmetric ill-defined nodules in a peribronchovascular distribution, fissural nodularity, mediastinal adenopathies, and pleural effusions. Correlation between the high-resolution computed tomography findings and the pathology revealed by histopathological analysis demonstrate that the areas of central peribronchovascular infiltration represent tumor growth involving the bronchovascular bundles, with nodules corresponding to proliferations of neoplastic cells into the pulmonary parenchyma. The interlobular septal thickening may represent edema or tumor infiltration, and areas of ground-glass attenuation correspond to edema and the filling of air spaces with blood. These findings are a result of the propensity of Kaposi sarcoma to grow in the peribronchial and perivascular axial interstitial spaces, often as continuous sheets of tumor tissue.

In conclusion, radiological findings can play a major role in the diagnosis of pulmonary Kaposi sarcoma since characteristic patterns may be observed. The presence of these patterns in patients with AIDS is highly suggestive of Kaposi sarcoma.

Immune reconstitution inflammatory syndrome after initiating highly active antiretroviral therapy in HIV-infected children

The outcome of HIV infection has improved since the widespread availability of highly active antiretroviral therapy (HAART). Some patients, however, develop a clinical and radiological deterioration following initiation of HAART due to either the unmasking of occult subclinical infection or an enhanced inflammatory response to a treated infection. This phenomenon is believed to result from the restored ability to mount an immune response and is termed immune reconstitution inflammatory syndrome (IRIS) or immune reconstitution disease. IRIS is widely reported in the literature in adult patients, most commonly associated with mycobacterial infections. There is, however, a paucity of data documenting the radiological findings of IRIS in children. Radiologists need to be aware of this entity. As a diagnosis of exclusion it is essential that the radiological findings be assessed in the context of the clinical presentation. This article reviews the common clinical and radiological manifestations of IRIS in HIV-infected children.