|Year : 2018 | Volume
| Issue : 2 | Page : 68-71
Silent Sinistrous Asymptomatic Anterior Mediastinal Mass Diagnosed With EBUS-TBNA
Deepak Prajapat, Rahul Kumar Sharma, Deepak Talwar
Metro Centre for Respiratory Diseases, Metro Multispecialty Hospital, Noida, Uttar Pradesh, India
|Date of Web Publication||10-Jul-2018|
Rahul Kumar Sharma
Metro Centre for Respiratory Diseases, Metro Multispecialty Hospital, Sector 11, Noida, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
The most common cause of asymptomatic anterior mediastinal mass in young patient is thymoma. We present an unusual case of asymptomatic anterior mediastinal mass in a young male who was incidentally discovered to have aggressive precursor T-cell adult lymphoblastic lymphoma (T-ALL). Routine bronchoscopy and transthoracic needle aspiration were noncontributory, and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) provided the adequate amount of tissue for histopathology and immunohistochemistry, thus establishing the diagnosis of T-ALL. Our case highlights T-cell lymphoma as a cause of silent anterior mediastinal mass and the potential role of EBUS-TBNA as safe and relatively less invasive modality to obtain tissue for pathological diagnosis and saved the patient from potential thoracotomy/mediastinoscopy.
Keywords: Anterior mediastinal mass, endobronchial ultrasound guided transbronchial needle aspiration, T-cell adult lymphoblastic lymphoma
|How to cite this article:|
Prajapat D, Sharma RK, Talwar D. Silent Sinistrous Asymptomatic Anterior Mediastinal Mass Diagnosed With EBUS-TBNA. J Assoc Chest Physicians 2018;6:68-71
|How to cite this URL:|
Prajapat D, Sharma RK, Talwar D. Silent Sinistrous Asymptomatic Anterior Mediastinal Mass Diagnosed With EBUS-TBNA. J Assoc Chest Physicians [serial online] 2018 [cited 2019 Jun 19];6:68-71. Available from: http://www.jacpjournal.org/text.asp?2018/6/2/68/232962
| Introduction|| |
Anterior mediastinal masses are mostly present with respiratory symptoms (75.5%) due to mass effect on the trachea or bronchus. Physical examination and routine investigations are frequently noncontributory to the diagnosis. Overall, 25–49% of primary mediastinal tumors are malignant. Lymphoma commonly involves mediastinum, mostly present either as big mass (>10 cm) or multiple mediastinal lymph nodes. Hodgkins and non-Hodgkins lymphoma both are common in mediastinum but mostly are of B-cell origin. Adult lymphoblastic lymphoma is a rare form of aggressive, non-Hodgkin lymphoma (NHL) of T-cell origin, occurring in 1–2% of all NHLs and is usually symptomatic at presentation. We report an asymptomatic young male presenting with mediastinal mass detected on routine chest skiagram and utility of endobronchial ultrasound-guided fine needle aspiration (EBUS-FNA) in establishing the diagnosis of highly aggressive primary mediastinal adult T-cell lymphoblastic lymphoma.
| Case Report|| |
A 22-year-old male smoker was detected to have a radiological abnormality on routine pre-employment medical checkup and was sent for further evaluation. His vitals showed: blood pressure − 116/72 mmHg, respiratory rate − 18/min, pulse − 80/min, room air oxygen saturation − 96%. The chest revealed bilateral normal vesicular breath sounds and normal rest of the systemic examination. Chest skiagram revealed left upper zone homogenous opacity [[Figure 1]a]. Routine blood reports were normal. Serum beta-human chorionic gonadotropin (hCG), alpha-fetal protein (AFP), and lactate dehydrogenase were within normal limits. His lung functions were normal with normal diffusion capacity. Contrast-enhanced computerized tomography (CECT) of the chest revealed a soft tissue mass in anterosuperior mediastinum on the left side and extending caudally up to the left hilar region and measure approximately 5.5 cm × 5.4 cm × 6.7 cm with no vascular invasion or signs of compression of surrounding the mediastinal structures. No mediastinal or hilar lymphadenopathy was seen [[Figure 1]b]. Ultrasonography (USG) of whole abdomen revealed a small 8.6 mm hyperechoic calcified focus seen in the right lobe of liver, mild splenomegaly, and USG. Scrotum showed no significant abnormality. Magnetic resonance imaging (MRI) of the chest [[Figure 1]c] revealed the axial T2 weighted image, showing a lobulated lesion with bright signal intensity in the left para-aortic area with no involvement of nearby vasculature. CT-guided fine needle aspiration (CT-FNA) smears showed lymphoid cells mixed with epithelial component, extensive crush artifact with few large convoluted cells, and the possibility of thymoma was kept but the tissue was inadequate for further evaluation. The patient was planned for video assisted thoracoscopic surgery (VATS) excision biopsy but denied by the relatives.
|Figure 1: (a) Chest skiagram revealed the left upper zone homogenous opacity. (b) CECT of the chest revealed a soft tissue mass in anterosuperior mediastinum on the left side and extending caudally. (c) MRI of the chest revealed the axial T2W image, showing a lobulated lesion with bright signal intensity in the left para-aortic area with no involvement of nearby vasculature. (d) EBUS-TBNA from the mass, and the needle is shown inside the mass|
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The patient underwent fiberoptic bronchoscopy which showed normal tracheobronchial tree mucosa with no intrabronchial lesion or any evidence of extrinsic compression. Endobronchial ultrasound (EBUS) along the left subcarina superiorly revealed large homogenous mass with no internal heterogenous echoes, necrosis, or calcification. EBUS-guided transbronchial needle aspiration (TBNA) from the mass was performed [[Figure 1]d]. Ziehl Nelson and para-amino salicylic acid stains on bronchoalveolar lavage were negative for organisms. Cell block from EBUS aspirate showed infiltration by small, round cells with hyperchromatic nuclei and inconspicuous nucleoli suggestive of thymo-lymphoma [[Figure 2]a]. Immunohistochemistry (IHC) on EBUS-cell block revealed CD3 [[Figure 2]b], CD5, CD99 [[Figure 2]c], CD1a-positive. Terminal deoxynucleotidase transferase (TdT) was also positive [[Figure 2]d] in the majority of cells; therefore, the final diagnosis of T-cell neoplasm, that is, precursor T-cell lymphoblastic lymphoma was established obviating the need of VATS biopsy. Bone marrow aspiration was performed, which shows lymphoblast cells <25% of total population and hence leukemia was excluded. MRI of the brain and cerebrospinal fluid analysis (CSF) were normal. He underwent chemotherapy is on hyper-CVAD (cyclophosphamide, vincristine, doxorubicin, dexamethasone) regimen presently and doing well after 2 years.
|Figure 2: Immunohistochemistry (IHC) on EBUS-cell block revealed: (a) CD3 positivity and (b) CD99 positivity. (c) CD1a positivity and (d) TdT positivity seen in T-cell neoplasm|
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| Discussion|| |
Mediastinum is a closely surrounded space. The location of tumor in mediastinum, age of presentation, and symptoms indicate toward the possible cause, yet they pose a significant challenge for the diagnosis. Approximately 2/3rd of mediastinal masses are benign in nature. The study by Davis et al. of 400 patients showed that 59% of masses in anterior mediastinal mass were malignant, whereas 29% of middle mediastinal masses were malignant., The presentation of lymphomas and germ cell tumors is between the second and fourth decades of life. The common differential diagnoses of anterior mediastinal masses include thymoma, teratoma, lymphoma, carcinoma, parathyroid adenoma, and intrathoracic goiter.
Primary lymphoma of mediastinum is a rare entity and seen in only 1–3% of mediastinal masses. The most common mediastinal lymphoma is Hodgkins (50–70%), while NHL is seen in only 15–25%. Lymphoblastic lymphoma has different clinical phenotypes which can be of either T-cell or B-cell origin. T-cell adult lymohoblastic lymphoma (T-ALL) is typically a presentation of adolescents and young age with a male predominance (3:1) and shown to have bimodal age distribution in men (peaking between the age 10–30 and 60–70 years), while distribution is more even in females. It is considered to be highly aggressive tumor, arising from thymic lymphocytes with common presentation of cough, wheezing, or shortness of breath but may also have presentations such as superior vena cava syndrome, cardiac tamponade, or tracheal obstruction. The most common cause of seeking medical attention in these patients are tracheal compression or chest pain. Other than serological markers such as AFP and hCG secreted by germ cell tumors, non of the routine investigation is abnormal at presentation. Up to 2/3 of T-cell lymphoblastic lymphoma, when present with medistinal mass, is bulky. In contrast, thymomas are typically encapsulated, well-defined, soft-tissue mass, sometimes associated with hemorrhage, necrosis, or cyst formation. Contrary to these presentations, our patient was asymptomatic and it was an incidental finding on a routine CXR. MRI is more valuable to evaluate the extent of vascular invasion, presence of fat, calcification, fluid, or cardiac involvement, but did not show any such invasion on MRI scans of our case. Masses other than thymoma required a tissue diagnosis before surgical resection but the success of less invasive fine-needle aspiration (CT- or USG-guided) is operator-dependent and contingent on the skill of the immunohistologist. In lymphomas, tissue diagnosis should be obtained before treatment. Flow cytometry, IHC, and cytogenetic analysis are usually utilized for obtaining a definitive diagnosis, because in our case, most likely clinic radiological diagnosis was thymoma and might have opted for surgical excision, which is clearly unwarranted in the primary mediastinal lymphoma. The diagnosis of mediastinal masses are challenging for the clinician. TBNA or CT-FNA is the most common initial modality used for tissue extraction to reach histopathological diagnosis; however, many remain undiagnosed and require more invasive procedures such as mediastinoscopy, which is an invasive surgical procedure that poses a small but significant risk. EBUS-TBNA is a minimally invasive and safe approach for the sampling of the paratracheal or parahilar lesions, because it enables aspiration under real-time ultrasonographic vision. It is a well-established tool for the diagnosis, staging, and restaging of lung cancer, and the yield of EBUS-TBNA is over 78% patients with undiagnosed tumors of mediastinum where two-thirds were malignant. Lymphoma diagnosis has been reported in up to 25% of nonlymph nodal lesions of mediastinum on EBUS-FNA but low-volume specimens were a concern requiring surgical biopsy for the detailed examination of the tissue. Lymphoblastic lymphomas have been grouped with acute lymphoblastic leukemias by the latest version on the World Health Organization classification system, because they are morphologically and immunophenotypically indistinct. Lymphoma from leukemia is differentiated when <25% bone marrow is involvement. In our case, BM was not involved at the time of diagnosis. As the involvement of CNS is high in these cases, MRI of the brain and CSF were performed, and they were found to be normal.
Combination chemotherapy has shown to give excellent response but relapses are common. Adults are treated with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or CHOP-like regimens, and response rates vary from 55 to 95%. Hyper-CVAD regimen given to our patient is reported to generate nearly 100% response with overall 70% survival benefit but 40–60% eventually relapse.
- Asymptomatic mediastinal mass is a rare presentation of T-ALL in young patients.
- This case highlights the use of EBUS-FNA as a useful and less invasive alternative to obtain satisfactory amount of tissue for the diagnosis of mediastinal masses not explained by conventional diagnostic work-up.
- Samples from EBUS-FNA can be utilized for IHC along with histopathology to establish the diagnosis of primary mediastinal T-cell lymphoblastic lymphoma.
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
Conflicts of interest
There are no conflicts of interest.
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