The idiopathic hypereosinophilic syndrome

Interstitial lung diseases-can pathologists arrive at an etiology-based diagnosis? A critical update

Interstitial lung diseases (ILD) encompass a group of diseases with a wide range of etiologies and a variety of tissue reactions within the lung. In many instances, a careful evaluation of the tissue reactions will result in a specific diagnosis or at least in a narrow range of differentials, which will assist the clinician to arrive at a definite diagnosis, when combining our interpretation with the clinical presentation of the patient and high-resolution computed tomography. In this review, we will exclude granulomatous pneumonias as well as vascular diseases (primary arterial pulmonary hypertension and vasculitis); however, pulmonary hypertension as a complication of interstitial processes will be mentioned. Few entities of pneumoconiosis presenting as an interstitial process will be included, whereas those with granulomatous reactions will be excluded. Drug reactions will be touched on within interstitial pneumonias, but will not be a major focus. In contrast to the present-day preferred descriptive pattern recognition, it is the author's strong belief that pathologists should always try to dig out the etiology from a tissue specimen and not being satisfied with just a pattern description. It is the difference of sorting tissue reactions into boxes by their main pattern, without recognizing minor or minute reactions, which sometimes will guide one to the correct etiology-oriented interpretation. In the author's personal perspective, tissue reactions can even be sorted by their timeliness, and therefore, ordered by the time of appearance, providing an insight into the pathogenesis and course of a disease. Also, underlying immune mechanisms will be discussed briefly as far as they are essential to understand the disease.

Mucocutaneous Splendore-Hoeppli phenomenon

Splendore-Hoeppli phenomenon (asteroid bodies) is the in vivo formation of intensely eosinophilic material (radiate, star-like, asteroid or club-shaped configurations) around microorganisms (fungi, bacteria and parasites) or biologically inert substances. This study presents a literature review concerning Splendore-Hoeppli reaction in the mucocutaneous diseases. It examines the histopathological features, nature and differential diagnosis of this reaction. It also discusses the mucocutaneous infections and the non-infective diseases associated with it. Available studies indicate that several mucocutaneous infections can generate Splendore-Hoeppli reaction. The fungal infections include sporotrichosis, pityrosporum folliculitis, zygomycosis, candidiasis, aspergillosis and blastomycosis. The bacterial infections include botryomycosis, nocardiosis and actinomycosis. The parasitic conditions include orbital pythiosis, strongyloidiasis, schistosomiasis and cutaneous larva migrans. In addition, Splendore-Hoeppli reaction may be seen with non-infective pathology such as hypereosinophilic syndrome and allergic conjunctival granulomas. The Splendore-Hoeppli reaction material comprises antigen-antibody complex, tissue debris and fibrin. Although the exact nature of this reaction is unknown, it is thought to be a localized immunological response to an antigen-antibody precipitate related to fungi, parasites, bacteria or inert materials. The characteristic formation of the peribacterial or perifungal Splendore-Hoeppli reaction probably prevents phagocytosis and intracellular killing of the insulting agent leading to chronicity of infection. To conclude, Splendore-Hoeppli reaction is a tell tale of a spectrum of infections and reactive conditions. The molecular pathways involved in the development of this reaction are open for future investigations.

Unusual case of aortic valve involvement in patient with Löffler’s Endomyocarditis: management, follow-up and short review of the literature

Idiopathic hypereosinophilic syndrome (IHES) is an uncommon systemic disease which is characterised by blood eosinophilia and multiple clinical presentations. Cardiac involvement is the major cause of mortality and morbidity. Here we describe a 59-year-old man with symptoms of progressive dyspnea on exertion, and productive cough as an unusual case of Löffler endomyocarditis with a mass on the aortic valve which showed regression with treatment.

Biology of platelet-derived growth factor and its involvement in disease

Platelet-derived growth factor (PDGF) is mainly believed to be an important mitogen for connective tissue, especially for fibroblasts that serve in wound healing. However, PDGF also has important roles during embryonal development, and its overexpression has been linked to different types of fibrotic disorders and malignancies. Platelet-derived growth factor is synthesized by many different cell types, and its expression is broad. Its synthesis is in response to external stimuli, such as exposure to low oxygen tension, thrombin, or stimulation by other cytokines and growth factors. In addition, PDGF may function in autocrine stimulation of tumor cells, regulation of interstitial fluid pressure, and angiogenesis. Recently, several drugs were developed that are potent inhibitors of the tyrosine kinase activity of PDGF receptors. Thus, it is important to understand the physiology of PDGF and its receptors and the role of PDGF in different diseases. This review summarizes the physiologic activity of PDGF, the expression of PDGF during embryonal development, and the roles of PDGF expression in nonmalignant disease and in different tumors.

Peripheral T-cell lymphoma-unspecified (PTCL-U) presenting with hypereosinophilic syndrome and pleural effusions

Hypereosinophilic syndrome (HES) is a clinical disorder characterized by persistent eosinophilia and systemic involvement, in which a specific causative factor for the eosinophilia cannot be verified during a certain period of time. There have been only a few reported cases of this syndrome associated with malignant lymphoma. We report a case of peripheral T-cell lymphoma-unspecified with hypereosinophilic syndrome. The patient was a 42-year-old woman with an uncontrolled fever and a sore throat. Eosinophilia was observed on the peripheral blood smear. We confirmed the diagnosis by bone marrow and liver biopsies:. A bone marrow aspiration demonstrated markedly increased eosinophils (24.8%), and a liver biopsy demonstrated infiltration by scattered eosinophils and atypical lymphoid cells, which were confirmed to be T-cell lymphoma cells. This case was a distinctive presentation of peripheral T-cell lymphoma with hypereosinophilic syndrome, probably due to a paraneoplastic condition.

Imatinib Mesylate Treatment in Two Patients with Idiopathic Hypereosinophilic Syndrome

OBJECTIVE:

To report 2 clinical cases of hypereosinophilic syndrome (HES) refractory to standard therapy and the variable responses to imatinib mesylate, and to review previously reported cases of imatinib mesylate use in the treatment of hypereosinophilia.

CASE SUMMARIES:

Two male patients were diagnosed with idiopathic HES complicated with organ involvement. Both were treated with imatinib mesylate after failing to respond to or being unable to tolerate standard therapy. In one patient, treatment with imatinib mesylate 100 mg/day produced resolution of symptoms and peripheral blood cell counts within 6 days. The patient has successfully maintained normal blood cell counts and has been without symptoms for more than one year after starting imatinib mesylate. The other patient failed to respond to imatinib mesylate even at the maximum dose (up to 400 mg/day).

DISCUSSION:

Imatinib mesylate was considered an appropriate alternative for standard therapy of HES based on the evidence that other treatments used for chronic myelogenous leukemia have also been successful in treating HES. Three small studies have supported this hypothesis. However, not all patients with HES respond to imatinib mesylate therapy. The cases presented here illustrate the marked difference.

CONCLUSIONS:

Imatinib mesylate has shown some promise in the treatment of HES. However, until the etiology of idiopathic hypereosinophilia and the role of imatinib mesylate in the resolution of this disease are determined, it will continue to be difficult to predict the responsiveness of a patient to imatinib mesylate therapy.