Pulmonary Langerhans cell histiocytosis: emerging concepts in pathobiology, radiology, and clinical evolution of disease

A young man with multiple pulmonary cysts

Several diseases cause cystic or cyst-like parenchymal lung abnormalities including adult pulmonary Langerhan's cell histiocytosis (PLCH), lymphangioleiomyomatosis (LAM), emphysema, end-stage interstitial lung disease, and cystic bronchiectasis. Many of these diseases can now be diagnosed with high accuracy by the use of high-resolution computerized tomography (HRCT). In fact, HRCT of chest has proved a major breakthrough in the diagnosis of these diseases. We are presenting a young man with a cystic lung disease in which, the HRCT findings were virtually diagnostic of that disease. The clinical and HRCT findings of this disease along with its differential diagnosis are discussed in this paper.

Langerhans cell histiocytosis: update for the pediatrician

PURPOSE OF REVIEW

Langerhans cell histiocytosis is the commonest of the histiocytic disorders. Owing to the relative rarity of the condition, it remains a disease in which the diagnosis is often delayed or missed and in which many questions remain unanswered, ranging from etiology and pathogenesis to therapy. The management is often frustrating for care-givers and parents/patients. The purpose of the review is therefore to raise awareness of the disease and to highlight the clinical findings that should make the pediatrician or primary care-giver suspect the diagnosis, as well as current thinking regarding management of the various and diverse manifestations of this disease.

RECENT FINDINGS

We discuss new and interesting insights into the biology of Langerhans cell histiocytosis that raise the possibility of future targeted therapy. Important points in the diagnosis, investigation and management of the various forms of the disease are also discussed.

SUMMARY

We present a review of childhood Langerhans cell histiocytosis, highlighting new insights into pathogenesis and management of the various forms of this complex disease.

Immunohistochemical Analysis of Langerin in Langerhans Cell Histiocytosis and Pulmonary Inflammatory and Infectious Diseases

Pulmonary Langerhans cell histiocytosis (LCH) is an idiopathic condition affecting predominantly adult smokers. Histologically, LCH is characterized by a nodular, interstitial proliferation of Langerhans cells around the distal airways with associated eosinophils, lymphocytes, and macrophages. Associated findings, such as fibrosis, emphysematous change, and bronchiolitis can be reminiscent of other interstitial lung diseases. The markers CD1a and S100 have traditionally been used to distinguish LCH from other processes. Little is known about expression of the Langerhans cell-specific lectin, langerin, in pulmonary diseases. We examined the expression patterns of S100, CD1a, and langerin in LCH and other interstitial, inflammatory, and infectious processes in cases retrieved from the files at Brigham and Women's Hospital Department of Pathology. Immunoreactivity was scored according to the number of cells staining per high power field (400x) in areas of highest density, averaged over 4 fields. Cases diagnosed as LCH based on histomorphology and positive CD1a and S100 staining demonstrated strong langerin positivity in lesional tissue. All cases of LCH contained greater than 30 langerin and CD1a positive cells per high power field (HPF), with a mean of >100 cells per HPF, in lesional tissue. Of the other interstitial processes examined, only usual interstitial pneumonia demonstrated increased number of Langerhans cells within epithelium and interstitium (mean 14 cells per HPF) as compared with normal lung (mean 6 cells per HPF). Langerin and CD1a serve as specific diagnostic markers in distinguishing LCH from other interstitial and inflammatory processes.

Pulmonary hypertension in patients with interstitial lung diseases

Pulmonary hypertension (PH) in patients with interstitial lung diseases (ILDs) is not well recognized and can occur in the absence of advanced pulmonary dysfunction or hypoxemia. To address this topic, we identified relevant studies in the English language by searching the MEDLINE database (1966 to November 2006) and by individually reviewing the references of identified articles. Connective tissue disease-related ILD, sarcoidosis, idiopathic pulmonary fibrosis, and pulmonary Langerhans cell histiocytosis are the ILDs most commonly associated with PH. Pulmonary hypertension is an underrecognized complication in patients with ILDs and can adversely affect symptoms, functional capacity, and survival. Pulmonary hypertension can arise in patients with ILDs through various mechanisms, Including pulmonary vasoconstriction and vascular remodeling, vascular destruction associated with progressive parenchymal fibrosis, vascular inflammation, perivascular fibrosis, and thrombotic angiopathy. Diagnosis of PH in these patients requires a high index of suspicion because the clinical presentation tends to be nonspecific, particularly in the presence of an underlying parenchymal lung disease. Doppler echocardiography is an essential tool in the evaluation of suspected PH and allows ready recognition of cardiac causes. Right heart catheterization is needed to confirm the presence of PH, assess its severity, and guide therapy. Management of PH in patients with ILDs is guided by identification of the underlying mechanism and the clinical context. An increasing number of available pharmacologic agents in the treatment of PH allow possible treatment of PH in some patients with ILDs. Whether specific treatment of PH in these patients favorably alters functional capacity or outcome needs to be determined.

Pulmonary Langerhans cell histiocytosis: a variable disease in childhood

BACKGROUND

Pulmonary Langerhans cell histiocytosis (PLCH) is rare in childhood but occurs most commonly in children with multisystem (MS) LCH. In adults, by contrast, the lung is the most common and usually the sole organ affected. This retrospective study describes the clinical manifestation, course, and outcome of PLCH in children consecutively diagnosed at two Canadian institutions.

PROCEDURE

The medical records of children (<18 years of age) consecutively diagnosed with LCH at the two institutions, were examined to ascertain the demographic details, pathological diagnosis, and organs involved. Further clinical details including, the clinical manifestation, details of therapy, course of lung disease, and clinical outcome were extracted for patients with PLCH. Initial and follow-up lung radiographs and CT scans were re-reviewed.

RESULTS

Of the 178 patients with LCH, 40 (22.5%) presented with MS disease. Thirteen (7.3%) had PLCH, seven at initial diagnosis, and six at the time of disease progression. The median age was 10.1 months and mean was 11.9 months at diagnosis of PLCH. Lung involvement was always in the context of MS LCH, and half of the patients had no respiratory symptoms. Disease-free survival was around 70%, with a mean follow-up duration of 7 years. Of the four patients who died, three had other risk-organ involvement. Five of the nine surviving patients have had complete radiological resolution of PLCH.

CONCLUSION

PLCH is seen in less than 10% of childhood LCH, but more than 30% of MS LCH. About half of children with PLCH may be asymptomatic, and the prognosis appears to depend on the presence or absence of other risk-organ involvement. The MS PLCH found in children appears to be a different disease from the single system (SS) PLCH seen in adults.

Uncommon causes of cough: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To describe the uncommon causes of cough.

DESIGN/METHODOLOGY

An English language literature search by MEDLINE citations from 1975 through 2004 was used to identify publications on uncommon pulmonary and nonpulmonary disorders in which cough was present as the major or presenting symptom in >50% of those persons affected by the uncommon diseases.

RESULTS

A substantial number of uncommon or rare pulmonary and nonpulmonary disorders were identified. The uncommon occurrence of these diseases made it difficult to develop a meaningful evidence-based guideline to the diagnosis and therapy of many of the uncommon causes of cough. As cough was the major or presenting symptom, it was usually initially attributed to common respiratory diseases (eg, asthma or bronchitis). As a result, a substantial time lag existed from the onset of cough to the diagnosis of the etiologic entity. Diagnostic tests limited to the respiratory system did not always provide clues to the diagnosis of uncommon causes of cough.

CONCLUSIONS

Cough is the major or presenting symptom in many uncommon pulmonary and nonpulmonary disorders. A strong index of suspicion is essential to consider and diagnose the uncommon causes of cough. The diagnosis and management of cough in patients with uncommon causes of cough is dependent on the underlying etiology.

Natural Course of Isolated Pulmonary Langerhans’ Cell Histiocytosis in a Toddler

Isolated pulmonary Langerhans' cell histiocytosis (LCH) is distinctly rare under the age of 15 years, since the majority of patients are young adult males with heavy smoking habits. Isolated pulmonary involvement suggests that antigens inhaled from cigarette smoke are involved. Here we present a case of LCH restricted to the lungs in a toddler whose parents were heavy smokers. Since LCH was not medically treated for 3 years due to parental refusal, the disease can be regarded as having followed its natural course. During the 3-year follow-up, the disease progressed to severe pulmonary fibrosis resulting in honeycomb lungs. Based on the comparative immunohistochemical analyses of the cells obtained from bronchoalveolar lavages during the disease course, it appears that the evolution of fibrosis is rather a result from the accumulating alveolar macrophages than from the persistence of the Langerhans' cells. Passive cigarette smoking may be considered a significant risk factor in both the pathogenesis and development of pulmonary LCH in a small child.

High-Resolution CT in Diagnosis of Diffuse Infiltrative Lung Disease

The chest radiograph remains the first imaging modality for the approach to diffuse infiltrative lung disease (DILD), but, 23 years after its introduction, high-resolution CT (HRCT) is still considered the best imaging tool for the evaluation of the pulmonary interstitium and to diagnose and assess DILD. The introduction of multidetector computed tomography (MDCT) has provided the thoracic radiologist with a powerful tool with which to image the lung. Moreover MDCT has enabled radiologists to understand better the functional information contained within CT images of DILD. By focusing on the HRCT signs, patterns, and distributions of abnormalities, and mentioning the clinical aspects and the new recent advances in pulmonary imaging, in this article we provide an overview of a practical approach to the interpretation of the DILD.

Obstructing tracheal pulmonary Langerhans cell histiocytosis

Pulmonary Langerhans cell histiocytosis, also known as eosinophilic granuloma, is an uncommon interstitial lung disease. A solitary nodule, usually parenchymal, may rarely be the only manifestation of the disease. We describe a case of Langerhans cell histiocytosis presenting as an obstructing tracheal lesion in a 55-year-old woman. Following complete resection of the lesion via flexible bronchoscopy, full recovery was achieved. This case represents a unique cause for tracheal obstruction, as well as an unreported manifestation of pulmonary Langerhans cell histiocytosis.

Incipient stage of pulmonary Langerhans-cell histiocytosis complicated with pulmonary tuberculosis was examined by high-resolution computed tomography

A 29-year-old man with a smoking history of 20 pack years was diagnosed with tuberculosis because Mycobacterium tuberculosis was detected in his gastric juice. His chest radiograph showed multiple nodular opacities on left upper lobe. He was treated with anti-tuberculosis drugs in our hospital. Six months after the therapy, he began to complain of dry cough and shortness of breath on exertion. Chest radiograph showed reticular opacities in both upper and middle lung fields. Multiple thick- and thin-walled bizarre-shaped cysts and ill-defined centrilobular opacities were seen mainly in upper and mid-lungs on high-resolution computed tomography (HRCT). He was diagnosed with pulmonary Langerhans-cell histiocytosis (PLCH) by transbronchial lung biopsy specimens from right upper lobe. HRCT findings before the treatment of tuberculosis were retrospectively examined. Several small thin-walled centrilobular cysts were scattered in the right upper and middle lung fields without apparent nodular lesions. We must consider the possibility of PLCH when these findings are detected on HRCT.

Histiocitose de células de Langerhans: rápida resolução após cessação do tabagismo

Descreve-se um caso de histiocitose pulmonar de células de Langerhans com relação estreita entre cessação do tabagismo e melhora radiológica. A tomografia computadorizada de alta resolução revelava múltiplos nódulos pequenos localizados em lobos superiores e campos médios de ambos os pulmões. O exame microscópico dessas lesões mostrava infiltração histiocitária, que se corava fortemente pela proteína S100. Apesar de a remissão espontânea poder ser uma possível explicação para essa evolução, este relato de caso mostra um rápido desaparecimento das lesões após o abandono do tabagismo.

A case of disseminated Langerhans' cell histiocytosis treated with thalidomide

Tumor necrosis factor alpha (TNF-alpha) seems to play a key role in the pathogenesis of Langerhans' cell histiocytosis (LCH). Thalidomide is an immunomodulator agent of inflammatory cytokines including TNF-alpha. To our knowledge this is the first case of disseminated LCH successfully treated with thalidomide.

A case of multiorgan Langerhans' cell histiocytosis presented with pneumothorax

Pulmonary Langerhans' cell histiocytosis (LCH) represents an uncommon clinical disorder with unpredictable clinical presentation and outcome. Lung involvement may occur either in isolation or as part of a multiorgan disease. A 43-year-old woman was admitted to our hospital with acute left chest pain and shortness of breath. Spontaneous left pneumothorax was detected. All laboratory tests, including pulmonary function studies, were normal. Radiological findings posed high suspicion for LCH and lung biopsy confirmed this diagnosis. Further studies identified small cystic lesions in the scalp and liver. The diagnosis of multiple organ LCH involvement was made. Spontaneous pneumothorax might be the presenting clinical symptom of LCH. The present case emphasizes the capricious nature of LCH and the importance of an individualized therapeutic approach.