Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2019  |  Volume : 62  |  Issue : 4  |  Page : 595--598

Type I pleuropulmonary blastoma presenting as congenital pulmonary airway malformation: A report of two cases


Kalpana Kumari1, Moanaro Longchar1, Ganganath Gunathilaka2, Priyanka Narange3, Sandeep Aggarwal4, Sudheer Arava1,  
1 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
2 Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
3 Department of Radiology, All India Institute of Medical Sciences, New Delhi, India
4 Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Sudheer Arava
Department of Pathology, All India Institute of Medical Sciences, New Delhi - 110 029
India

Abstract

Pleuropulmonary blastoma (PPB) is a rare aggressive intrathoracic tumor which is believed to originate from embryonic uncommitted lung mesenchymal cells, which are important for developing the lung. Type I PPB is cystic, type II is cystic and solid, while type III is predominantly solid. Diagnosing type 1 PPB is a challenge for both radiologists as well as pathologists. Owing to its purely cystic nature, type I PPB it is often mistaken for unrelated entities such as congenital pulmonary airway malformation and congenital lobar emphysema which delays surgical intervention. Here, we report two such cases presenting clinically and radiologically as congenital pulmonary airway malformation. On histology, a final diagnosis of type I pleuropulmonay blastoma was made. Thereafter, chemotherapy was administered following complete surgical excision.



How to cite this article:
Kumari K, Longchar M, Gunathilaka G, Narange P, Aggarwal S, Arava S. Type I pleuropulmonary blastoma presenting as congenital pulmonary airway malformation: A report of two cases.Indian J Pathol Microbiol 2019;62:595-598


How to cite this URL:
Kumari K, Longchar M, Gunathilaka G, Narange P, Aggarwal S, Arava S. Type I pleuropulmonary blastoma presenting as congenital pulmonary airway malformation: A report of two cases. Indian J Pathol Microbiol [serial online] 2019 [cited 2021 Dec 1 ];62:595-598
Available from: https://www.ijpmonline.org/text.asp?2019/62/4/595/269082


Full Text



 Introduction



Pleuropulmonary blastoma (PPB) is a rare, aggressive malignant tumor of infancy and early childhood which was first recognized in 1988.[1],[2] Tumor is analogous to other organ-based tumor of early childhood such as Wilms tumor and neuroblastoma.[1],[2] PPB exclusively affects children of age <6 years. Type I PPB has propensity to progress to types II and III PPB which represents solid high grade, multipatterned sarcomas.[3] Very often these benign appearing cysts are misdiagnosed as congenital pulmonary airway malformation (CPAM).[4],[5] Recognizing this entity is important, since type 1 PPB has better outcome and complete surgical resection can prevent tumor progression. Here we present two cases of PPB type I radiologically presenting as CPAM.

Case 1

A 2-year-girl child was admitted for the management of complicated right sided pleural effusion. At the age of 1 month, she developed acute febrile illness with respiratory distress and was treated at local hospital. However, her condition deteriorated, developed hydropneumothorax and was admitted to our institute. Patient was hypertensive. Her elder brother had been diagnosed with neuroblastoma for which he underwent treatment. Chest radiograph revealed opacification of right hemi-thorax with significant contralateral mediastinal shift for which pigtail catheter drainage was done based on radiographic findings. Contrast enhanced computed tomography (CECT) of chest showed a large, multiloculated cystic lesion arising from the right upper lobe, measuring 9 cm × 8.5 cm × 3 cm, accommodating almost the entire right hemi-thorax, with mild pleural effusion [Figure 1]. A clinico-radiological diagnosis of CPAM type 1 with suspicion of PPB was considered. Thereafter, patient underwent right upper lobectomy and the surgical specimen was sent for histopathological examination. Grossly, cystic circumscribed lesion measuring 9 cm × 8.8 cm × 3 cm was identified [Figure 2]a. Cut surface showed a large cyst measuring 7.5 cm × 5 cm, the periphery of which showed multiple small cysts varying from 0.3 to 1 cm in diameter. Multiple sections examined from cystic area showed variable sized cystic spaces lined by pseudostratified ciliated columnar epithelium with focal squamous metaplasia and ulceration. Subepithelium showed dense chronic inflammation and at places discontinuous cambium layer-like zone with nodules of undifferentiated primitive cells [Figure 2]b. Frequent atypical mitotic figures were noted [Figure 2]c and [Figure 2]d. Immunohistochemically, the neoplastic cells stained for desmin and myogenin [Figure 2]e and [Figure 2]f, and were negative for MIC-2, cytokeratin, smooth muscle actin, synaptophysin, chromogranin and TTF-1. A final diagnosis of Type I PPB was made.{Figure 1}{Figure 2}

Case 2

A 1-month-old baby presented with history of nasal regurgitation of feeds since day 3 of birth. Chest radiograph revealed well defined, air filled, multicystic lesion with internal septations associated with pneumothorax [Figure 3]a. The patient's condition worsened further, with severe respiratory distress. Patient underwent left posterolateral thoracotomy and left upper lobectomy. Excised specimen measured 5 cm × 3 cm × 1.5 cm. Cut surface showed multicystic spaces varying in size from 0.2 to 0.5 cm with intervening thin septa. Microscopic examination showed predominantly multilocular cyst walls lined by cuboidal epithelium [Figure 3]b. On extensive sampling, focally cellular areas with primitive mesenchymal cell forming a thick cambium layer, and single focus of cartilaginous differentiation forming nodules were also seen [Figure 3]c and [Figure 3]d. Immunohistochemistry for vimentin was positive while desmin and myogenin were negative. A final diagnosis of type I PPB was made. Post-operatively, a combination of vincristine, doxarubicin, actinomycin-D and ifosphamide was advocated to both patients. There is no evidence of metastases or recurrence in both the patients after serial follow-up of average 2.5 and 2 years.{Figure 3}

 Discussion



PPB is a rare aggressive intrathoracic tumor which originates from embryonic uncommitted lung mesenchymal cells.[1],[2] Type I PPB is cystic, type II is cystic and solid, while type III is predominantly solid.[1],[2] Diagnosis of solid PPBs are straightforward based on location in lung, age of patient and multilineage differentiation.[6] However, diagnosing type I PPB is a challenge for both radiologists as well as pathologists. Due to its purely cystic nature type I PPB it is often mistaken for unrelated entities such as CPAM and intrapulmonary bronchogenic cysts which delays surgical intervention.[5],[6] In type I PPB, cyst septa contains focal areas of primitive mesenchymal cells, which may show differenciation along either skeletal muscle or cartilage and rarely lipomatous.[6] Immunohistochemical stains per se are not important for diagnosis, however, helps in characterizing the focal sarcomatous differentiation present in predominantly cystic background. Median age of presentation varies with the pathological type.[4],[7] Type I PPB usually presents in infants and young children (median: 10 months), while types II and III are identified in older age groups (median: 34 and 44 months, respectively).[4],[7] Type I PPB patients often present with symptoms of respiratory distress and pneumothorax due to rupture of air-filled cyst walls while pneumonic symptoms and large lung masses are the commoner presentation in PPB types II and III.[4],[7] Imaging performed reveals pneumonia or benign congenital cysts, particularly CPAM in majority of cases. Hence, diagnosis is misinterpreted and clinicians treats as a case of respiratory infection until patient develops complications like pneumothorax. Hence, for excised intrathoracic cyst, each thick septa should be sampled extensively. Since, delineating congenital pulmonary airway malformation (CPAM) patients from type I PPB will change treatment options and dramatically improves outcome.[4]

Mutations in DICER1 gene are known to be present in PPB patients and form a component of hereditary tumor predisposition syndrome.[7] Approximately 40% of children have personal or family history of other childhood cancers and benign lesions.[2] In the present Case 1, index elder brother was suffering from neuroblastoma. Interestingly, prevalence of Wilms tumor, neuroblastoma and medulloblastoma in patients harboring DICER 1 mutations is reported to be low.[7],[8] We were not able to perform mutation study in our patients and family members.

The common other differentials that should be considered before diagnosing type I PPB are as follows: (i) CPAM, (ii) simple lung cysts, (iii) cystic teratoma and (iv) bronchogenic cyst. Proper extensive sampling with careful examination of the microscopic sections will be necessary to come to a definitive diagnosis and to exclude other similar differentials.

 Conclusion



Benign appearing cystic lesions of lung on imaging should be sampled extensively to diagnose type I PPB. Identifying thickened or solid areas in the gross specimen will aid in the diagnosis, and is important, as early diagnosis of this entity will drastically improve the survival outcome in subsets of patients. Radiological screening should be performed for at-risk family members for early detection and better understanding of this inherited cancer syndrome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There is no conflicts of interest.

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