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  Table of Contents    
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


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

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Date of Web Publication14-Oct-2019
 

   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.

Keywords: Congenital cyst, congenital pulmonary airway malformation, pleuropulmonary blastoma

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;62:595-8

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 2019 Nov 22];62:595-8. Available from: http://www.ijpmonline.org/text.asp?2019/62/4/595/269082





   Introduction Top


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: (a) CT topogram show right-sided multiseptated (arrow) lesion with air fluid level and contralateral mediastinal shift (b: axial) and (c: coronal). Mediastinal window images shows large multicystic lesion with cysts of variables sizes (range: 2-8 cm) occupying right hemithorax. Along the periphery of cysts, focal solid enhancing areas (white arrow) were also noted. In addition, multiple tortuous vessels were noted coursing along the septa and peripheral walls of the lesion (black arrows). (d) Lung window shows the multicystic lesion with air fluid levels (white arrow)

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Figure 2: Gross photomicrograph showing a large cyst measuring 7.5 cm × 5 cm, the periphery of which showed multiple small cysts (range: 0.3-1 cm) (a). Microscopy shows a cyst wall lined by ciliated pseudostratified respiratory epithelium with loose mesenchymal stroma admixed with inflammatory cells in the subepithelium (b, ×100). Thick row of small primitive cells beneath the lining epithelium (c, ×100). Single focus of nodular aggregates of blue appearing primitive cells within the septa (d, ×100). Blastemal nodules diffusely immunopositive for desmin (e, ×100) and focally for myogenin (f, ×100)

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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: Frontal chest radiograph showing well-defined multicystic, air-filled lesion (arrows) with internal septations in left mid and lower zone. Tension pneumothorax (asterisks) present (a). Photomicrograph depicting a multilocular cystic lesion with areas of fresh hemorrhage (b, ×100). Small primitive cells forming cambium layer beneath cuboidal lining epithelium. Primitive blastemal component comprising of small round to oval hyperchromatic nuclei and scant cytoplasm admixed with spindled cells (c, ×100). Single tiny focus of nodule of primitive cartilage within the septa (d, ×100)

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   Discussion Top


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 Top


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.



 
   References Top

1.
Priest JR, Mc Dermott MB, Bhatia S, Watterson J, Manivel JC, Dehner LP. Pleuropulmonary blastoma: A clinicopathologic study of 50 cases. Cancer 1997;80:147-61.  Back to cited text no. 1
    
2.
Priest JR, Williams GM, Hill DA, Dehner LP, Jaffe A. Pulmonary cysts in early childhood and the risk of malignancy. Pediatr Pulmonol 2009;44:14-30.  Back to cited text no. 2
    
3.
Hill DA, Jarzembowski JA, Priest JR, Williams G, Schoettler P, Dehner LP. Type I pleuropulmonary blastoma: Pathology and biology study of 51 cases from the International Pleuropulmonary Blastoma Registry. Am J Surg Pathol 2008;32:282-95.  Back to cited text no. 3
    
4.
Priest JR, Hill DA, Williams GM, Moertel CL, Messinger Y, Finkelstein MJ, et al. Type I pleuropulmonary blastoma: A report from the International Pleuropulmonary Blastoma Registry. J Clin Oncol 2006;24:4492-8.  Back to cited text no. 4
    
5.
Miniati DN, Chintagumpala M, Langston C, Dishop MK, Olutoye OO, Nuchtern JG, et al. Prenatal presentation and outcome of children pleuropulmonary blastoma. J Pediatr Surg 2006;41:66-71.  Back to cited text no. 5
    
6.
Messinger YH, Stewart DR, Priest JR, Williams GM, Harris AK, Schultz KA, et al. Pleuropulmonary blastoma-a report on 350 central pathology-confirmed pleuropulmonary blastoma cases by the international pleuropulmonary blastoma registry. Cancer 2015;121:276-85.  Back to cited text no. 6
    
7.
Schultz KA, Yang J, Doros L, Williams GM, Harris AK, Stewart DR, et al. DICER I- pleuropulmonary blastoma familial tumor predisposition syndrome: A unique constellation of neoplastic conditions. Pathol Case Rev 2014;19:90-100.  Back to cited text no. 7
    
8.
Slade I, Bacchelli C, Davies H, Murray A, Abbaszadeh F, Hanks S, et al. DICER1 syndrome: Clarifying the diagnosis, clinical features and management implication of pleiotropic tumor predisposition syndrome. J Med Genet 2011;48:273-8.  Back to cited text no. 8
    

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Correspondence Address:
Sudheer Arava
Department of Pathology, All India Institute of Medical Sciences, New Delhi - 110 029
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/IJPM.IJPM_713_18

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