Aspergilloma in a hydatid cavity

1. Background 

Aspergiloma is the most common form of pulmonary aspergillosis, commonly developing in pre-existing lung cavities due to tuberculosis bronchestasis, ankylosing spondylitis, sarcoidosis or pulmonary infraction.1 Although, aspergilloma can also occur in hydatid cyst cavities, there are only a few cases in the literature in which aspergilloma have been reported to invade hydatid cyst cavities.

We report tow cases of coexistence of Aspergillosis and hydatid cyst. The pathophysiological mechanisms and therapeutic modalities are also discussed.

2. Case 1 

A 52-year-old Tunisian woman was admitted in our institution with 10-days history of left-sided chest pain, bloody sputum, fever, weight lose and fatigue.

Physical examination revealed a temperature of 38.1°C, blood pressure 130/70, pulse 100beats/minute, and respiration 26breaths/minute. All other systemic findings were normal. Chest X-ray revealed two left rounded cavitary lesions with an air-fluid level and a diameter of 2–3cm (Fig. 1). Routine biochemical tests and blood counts were normal. Repeated sputum smears were negative for acid-fast-bacilli. Despite ten days of empiric antibiotherapy, there was no clinical nor radiological improvement. Chest computed tomography (CT) scan revealed a thin walled regularly bordered cavitary lesion, which had a dimension of 3cm and was located in the dorso-apical segment of the left upper lobe. This lesion, neighbouring drainage bronchi, contains a mobile decline fluid collection. Another enhanced fluid-dense mass measuring 1.5cm of diameter was also noted in the upper segment of lingula. Since serological test for Aspergillus was positive, these radiological findings were interpreted as an aspergilloma. However, cavitary neoplasia was not excluded. A CT-guided fine-needle aspiration biopsy of the upper lesion was so performed. Histopathological examination revealed a laminated hyaline ectocystmembrane of Echinococcus better delineated on PAS stain (PAS: Priodic Acid of Schiff). There was no daughter vesicle or protoscolics. The material also contains fragments of inflammatory pericyst. Within the hydatid membrane, were embedded numerous septate hyphae branching at acute angle consistent with Aspergillus.

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Fig. 1 Chest X-ray reveals two rounded cavitary mass in the left lung field.

Therefore, the patient was diagnosed to have concurrent Aspergillus and Echinococus. In addition, indirect hemagglutination for Echinicoccus granulosus became positive. The patient was operated for the diagnosis of aspergilloma in an echinococcal cyst cavity. A left postero-lateral thoracotomy was performed. Pre-operative macroscopic examination showed in the left upper lobe tow indurate masses, which were removed by wedge resection. The lung tissue surrounding the lesions was healthy. Histopathological examination demonstrated a hyalin ectocyst surrounded by a thick fibrous pericyst in contact with slender septate hyphae branching at acute angle consistent with Aspergillus species. Thoracic drain was removed on the post-operative fourth day. Post-operatively, the patient developed a lung abscess in the left upper lobe. She was given intravenous ampicilline/clavulanic acid for 10 days (3grams daily). On the fourth hospital day, her temperature dropped and the radiological shadow decreased. Antibiotics treatment was changed to oral clavulanate–ampicilline and the patient was discharged at the end of the second week as cured. Systemic antifungal therapy was not initiated. One year after discharge, the patient remains asymptomatic, without recurrent aspergilloma or hydatid cyst in chest X-ray.

3. Case 2 

A 56-year-old Tunisian man with history of smoking at 60 paquets-year and recurrent hemoptysis for past 2 years. He was a known case of gastric ulcer and has received medical treatment. He was presented to our hospital with complain of severe hemoptysis, anorexia, generalized malaise and nocturnal sweet during the three past days. On admission, he was pale; his temperature was 37.5°C, heart rate 95beat/minute, respiratory rate 19/minute, and blood pressure 100/60mmHg. Decreased breath sounds over the right lower lung were also noted. Chest radiography revealed a 3cm rounded cavitary lesion with a crescent air sign over the right lower lung field (Fig. 2). The complete blood count and biochemistry were unremarkable except hypochromic, microcytic anaemia at 5.3g/dl. Examination for bacteria and Mycobacterium tuberculosis were negative. Chest Computed tomography scan confirmed the presence of a 3cm regularly cavitary mass with air crescent formation in the right lower lobe. This lesion was surrounded by Ground glass opacities and centrolobular micronodules, and was in communication with segmental bronchi (Fig. 3). These radiologic findings were considered as suggestive of infectious origin, particularly aspergilloma or hydatid cyst.

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Fig. 2 Chest radiography reveals a 3cm rounded cavitary lesion with a crescent air sign over the right lower lung field.

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Fig. 3 Chest CT scan shows a 3cm regularly cavitary mass with air crescent formation surrounded by ground glass opacities and centrolobular micronodules.

However, since the patient was a big smoking man and presented recurrent hemoptysis, malignancy was not excluded. We have tried to stop bleeding with haemostatic treatment (ocytocin) but in vain. After four globular sediment's transfusion, the patient underwent an exploratory and haemostatic thoracotomy under general anaesthesia for further diagnosis of the cavitary mass. At peroperative examination, there were no macroscopic abnormalities. Since malignancy was suspected and bleeding was massive, lower right lobectomy was performed with hilair and mediastinal lymph node dissection.

On histopathological examination, the mass was found to have numerous dichotomously branched septate hyphae with conidial heads suggestive of Aspergillus fumigatus. Interestingly these hyphae were embedded within a hydatid cyst lined by a thick hyaline ectocyst. Both septate hyphae and laminated ectocyst were better delineated on PAS and Gomori Grocott stains. The cyst was type IV (pseudotumoral) according to the Gharbi classification (Fig. 4).

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Fig. 4 (a) Histopathology slide showing fragmented laminated membrane of echinococcus (asterix) surrounded by suppurative necrosis; note numerous septate hyphae branching at acute angle embedded within necrosis (arrows) (hematoxylin eosinx 400). (b) Positive staining with Gomori Grocott for both ectocyst (asterix) and hyphae (arrows) (×400).

The patient progressed favourably, with an improvement of clinical symptoms, laboratory parameters, and respiratory function. The thoracic drain was kept 12 days after thoracotomy, and the patient was discharged without antifungal therapy. At the 6-month follow-up, the patient was asymptomatic and the thoracic CT was evaluated as being within normal limits.

4. Discussion 

Aspergilloma is the most common form of pulmonary aspergillosis. It occurs generally in pre-existing cavities caused in the most majority of cases by tuberculosis particularly in Tunisia where this infection is still endemic. Aspergilloma can also occur in operated hydatid cyst cavities, only a few cases have been reported.1, 2, 3, 4 The rarity of aspergilloma within hydatid cyst may be explained by the different elective site for the two diseases. In fact, the most common sites of aspergilloma and hydatid cyst are respectively the upper lobe and the lower lobe of the lung. The development of aspergilloma on cyst residual cavities can occur in the early post-operative period1 or many years after. However, in our cases, patients were diagnosed to have concurrent Aspergillus and Echinococcus. The coexistence of hydatid cyst and aspergillosis is extremely rare5: two cases were found out of the 100 reevaluated archival cases with a diagnostic of hydatid cyst.6 Such association has been reported in both immunocompromised and immunocompetent patients.6 In the two cases reported here, patients were immunocompetent and no structural abnormalities of the lung that may predispose to aspergillosis were found.

There is a number of pathophysiological mechanisms that can lead to the development of pulmonary aspergillosis and the clinical features are numerous.1, 2 This complication results from the deterioration in local defenses against opportunistic infections such as aspergilloma, Cryptococcus and phaeohypomycosis.1 It has been suggested also that in cases of giant hydatid cyst extending to the helium, refraining from obliterating the cyst cavities may lead to opportunistic infections such as aspergilloma.2

There is no typical clinic picture; however, the radiological aspects are more suggestive with a mobile, rounded, and bell-shaped cavity.1 The mobility of the opacity with a change of position is a strong pointer to the diagnosis of aspergilloma as shown in our first case. However, the sensitivity and specificity of imaging procedures in detecting the Aspergillus colonies entrapped in a hydatid cyst is not clear.6 In fact, tuberculosis, cavitary neoplasia, an intact hydatid cyst, or a necrotizing pulmonary abscess can also present with similar radiological features.2 In our cases, the radiological appearance was considered as suggestive of aspergilloma despite the absence of a known pre-existing lung cavity. Tuberculosis was also suspected but repeated sputum smears were negative for acid-fast-bacilli in both cases. Malignancy was particularly suspected in the second case because of smoking history and recurrent hemoptysis. Histopathological evaluation is essential for the diagnosis and for the planning of management. Cytopathologic examination of cyst aspirate may be effective when there is no contraindication for aspiration6 as was performed in the first case. We can as a result detect the coexistence of aspergilloma and hydatid cyst before operation and pre-plan adequate management. Surgery remains the main definitive treatment of this opportunistic pulmonary mycosis, despite the high-risk of post-operative morbidity and mortality. Recommended surgical treatment for aspergilloma includes lung resection for patients with adequate pulmonary function tests, as in our two cases, or cavernostomy in high-risk patients.2, 7 However, some authors consider that is more safely to indicate anatomic lung resection when aspergilloma is suspected pre-operatively.7 In the first case, since the lung tissue surrounding the lesions was healthy, we preferred wedge resection. In the second case, lobectomy was considered necessary because of suspicion of lung malignancy. Both of our patients progressed favourably without antifungal therapy. In fact, antifungal agents appear to provide suitable treatment for bronchopulmonary aspergillosis infection in immunocompromised patients. In aspergilloma, their efficacy is still unproved. It can be indicated if surgery is recused.5 Nevertheless, some authors propose to give antifungal therapy during the post-operative three months especially in cases with ruptured cysts and in immunocompromised patients who may be at risk of further Aspergillus infection.2, 6 Prognosis of aspergilloma is related to severity of subjacent lesions. The prognosis seems to be better if aspergilloma occurs within hydatid cyst than tuberculosis cavities.

In conclusion, we suggest that aspergillosis and hydatid cyst coexistence should be considered in the presence of pulmonary cavitary lesion particularly in endemic areas. Detecting such association before operation is important for planning adequate management.

Conflict of interest 

Authors have no conflict of interest.