Year : 2008 | Volume
: 25 | Issue : 2 | Page : 45--49
Diagnostic utility of fine needle aspiration cytology in pediatric tumors
Veena Maheshwari1, Kiran Alam1, Anshu Jain1, Surabhi Aggarwal1, RS Chana2,
1 Department of Pathology, JN Medical College, AMU, Aligarh, UP, India
2 Department of Surgery, JN Medical College, AMU, Aligarh, UP, India
2/82, Arya Nagar, Avantika Part - 2, Ramghat Road, Aligarh - 202 001, UP
Background and Aims: Fine needle aspiration cytology (FNAC) is a relatively new technique for the diagnosis of pediatric tumors. Most of the studies conducted so far have dealt only with malignant neoplasms or neoplasms of a particular organ/organ system in the pediatric population. Our work included a comprehensive study of both benign and malignant tumors in children younger than 15 years of age to correlate their clinical, cytological, and histological findings and to evaluate the effectiveness of FNAC in their diagnosis.
Materials and Methods: We studied 588 cases over a period of ten years. Data was collected retrospectively as well as prospectively, and included all patients younger than 15 years of age, who presented with tumors or associated symptoms. Clinical, cytological, and histopathological correlations were done.
Results: Benign soft tissue tumors formed the largest group among all pediatric tumors (41.5%). Lymphomas were the most common (25.1%) of all malignant tumors, followed closely by small round cell tumors (SRCTs, 21.3%). FNAC was performed in 342 (55.1%) cases, cyto-histological correlation was possible in 226 (38.4%) cases; and a concordant diagnosis was seen in 218 (37.1%) cases, giving an overall diagnostic accuracy of 96.46% with FNAC. Occasional rare cases like Dabska«SQ»s tumor and intraabdominal desmoplastic small round cell tumor could also be diagnosed by FNAC.
Conclusions: We conclude that FNAC is an effective method for the evaluation and screening of pediatric masses, as well as for follow-up of patients with a history of malignancy.
|How to cite this article:|
Maheshwari V, Alam K, Jain A, Aggarwal S, Chana R S. Diagnostic utility of fine needle aspiration cytology in pediatric tumors.J Cytol 2008;25:45-49
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Maheshwari V, Alam K, Jain A, Aggarwal S, Chana R S. Diagnostic utility of fine needle aspiration cytology in pediatric tumors. J Cytol [serial online] 2008 [cited 2022 Jul 2 ];25:45-49
Available from: https://www.jcytol.org/text.asp?2008/25/2/45/42440
Pediatric tumors differ markedly from adult tumors in their nature, distribution, and prognosis. Aspiration cytology, a well established technique in adult oncology, is now being increasingly applied to childhood tumors as it permits a rapid diagnosis with minimal trauma, morbidity, and a low complication rate. It also eliminates the need for anesthesia and hospitalization. The low cost of this procedure is especially advantageous in the Indian context.
Materials and Methods
The study group included children younger than 15 years of age attending the outpatient and inpatient departments of Pediatrics, Surgery, Orthopedic surgery etc. at a tertiary care center, and presenting with tumorous masses or associated symptoms. The study was conducted over a period of ten years, and the data was collected retrospectively from January 1997 to December 2001, and prospectively from January 2002 to December 2006. The cytological and histopathological examination was carried out in the Department of Pathology. Cytological smears were fixed in 95% alcohol, and stained with hemtoxylin and eosin, Papanicolaou, and May-Grünwald Giemsa stains. The Histopathological specimens were processed routinely and stained with hematoxylin and eosin (H and E).
Pediatric malignancies constituted 5% of all malignant tumors at our center. The age of the patients ranged from two months to 14 years. The majority of cases (40.82%) were seen in the 11-14 years' age group. Males were predominant in the study population, accounting for 392 cases (66.67%); with the male:female ratio being 2: 1. Out of a total of 588 cases, 381 (64.8%) of the tumors were benign and 207 (35.2%) were malignant. The majority of cases were of soft tissue tumors (44.1%), while the least were seen in the gastrointestinal tract (0.9%) [Table 1]. Fine needle aspiration cytology (FNAC) was done in 342 cases (55.1%). The majority of cases in which FNAC was not done were brain tumors (as burr hole aspiration was not possible), retinoblastomas, nasopharyngeal angiofibromas and hemangiomas. Tissue biopsy was not submitted in a few cases of lymphomas and Ewing's sarcoma.
Soft tissue tumors were also the most common category in benign tumors (64.1% of all benign cases), out of which tumors of vascular origin were the most common (38.9% of all benign tumors). FNAC was mostly inconclusive in hemangiomas, mainly showing blood. Cases of lymphangioma yielded slightly albuminous fluid with a few lymphocytes and histiocytes. Endothelial-like spindle cells having uniform ovoid nuclei, granular chromatin, and indistinct cytoplasm were seen in cases of hemangiopericytoma (three cases). A single case of Dabaska's tumor was reported in our study, which on FNAC, revealed hypercellular smears with two cell populations, viz , large eosinophilic cells having hyperchromatic nuclei, and spindle-shaped cells.  Cytoplasmic vacuolation was suggestive of the vascular origin.
Cases of fibroma yielded a few spindle-shaped cells with bland nuclei on FNAC. This was in contrast to the cellular smears observed in cases of fibrosarcoma, showing atypical spindle cells with elongated pleomorphic nuclei having coarse chromatin and increased mitotic activity.
Most cases of lipoma revealed mature adipocytes with clear cytoplasm and eccentric flattened nuclei. For the diagnosis of liposarcoma, atypical lipoblasts [Figure 1a] and atypical mitosis were the most important and helpful features. There were only two cases of angiolipoma, which yielded hemorrhagic smears along with a few fat cells. Clinical correlation (multiple painful nodules) helped us to reach the correct diagnosis.
Neurofibroma was the only nerve sheath tumor seen on FNAC. The smears showed spindle-shaped cells with bland chromatin in a fibrillary background.
Among tumors of muscular origin, only embryonal rhabdomyosarcoma was seen in our study. Smears revealed a pleomorphic population of round to spindle-shaped cells, with elongated hyperchromatic nuclei having high nucleocytoplasmic ratios.
In bone- and cartilage-derived tumors, smears from chondromas showed small chondrocytes in a background of pale chondroid ground substance. Osteochondromas yielded only blood and calcific debris, and hence, a cytological diagnosis could not be made in any of the cases. Multinucleated giant cells attached to the peripheries of sheets of spindle-shaped stromal cells, were seen in nearly all cases of giant cell tumors [Figure 1b]. Smears from cases of osteosarcoma showed pleomorphic spindle and round cells with multinucleated tumor giant cells and amorphous eosinophilic osteoid [Figure 1c].
The largest malignant group was formed by lymphomas (25.1% of all malignancies), followed by SRCTs (21.3%), and Wilms' tumor (12.6%). Only two variants of Hodgkin's lymphoma (HL) were observed in the present study, viz ., mixed cellularity (70% cases), and nodular sclerosis (30%). In mixed cellularity HL, smears showed numerous Reed Sternberg (RS) cells [Figure 2a], atypical mononuclear Hodgkin's cells, eosinophils, plasma cells, and histiocytes in a background population of lymphocytes. In contrast, a scanty aspirate was obtained in the nodular sclerosis variants, with a few fibroblasts and collagen fibers apart from RS cells, characteristic lacunar cells, eosinophils, plasma cells, and lymphocytes.
In cases of nonHodgkin's lymphoma (NHL), mostly there was a uniform population of immature lymphoid cells with variable mitosis [Figure 2b]. The exact typing was possible only after ancillary studies such as immunocytochemistry and flow cytometry. Smears from Burkitt's lymphoma (two cases) revealed a uniform small lymphoid population with granular chromatin, small nucleoli, and a starry sky appearance. Only one case was diagnosed as anaplastic large cell lymphoma (ALCL), which yielded large cells with abundant cytoplasm, lobulated nuclei, and prominent nucleoli.
In Ewing's sarcoma cases, cytology smears revealed a dual cell population, consisting of large pale cells with abundant periodic acid Sciff (PAS)-positive cytoplasmic vacuoles and small round cells with scanty cytoplasm and condensed nuclear chromatin [Figure 3a].
There were three cases of intraabdominal neuroblastoma, which on FNAC, showed numerous small malignant cells with scanty cytoplasm and nuclear moulding in a fibrillary background.
Smears from cases of Wilms' tumor showed varying combinations of blastemal, epithelial, and stromal elements along with necrosis, inflammatory cells, and occasional rosettes.
Smears from cases of adenocarcinoma rectum revealed groups of columnar cells with hyperchromatic nuclei showing pleomorphism and few signet ring cells [Figure 3b].
Most of the cases diagnosed as Ewing's sarcoma were referred to radiotherapy without doing tissue biopsy, and were found to respond well to treatment. A few cases of lymphomas and unclassified round cell tumors were referred to some other center, and a few patients, after an initial diagnosis on FNAC with clinicoradiological correlation, either left against medical advice or did not return for follow-up.
Thus, comparison of cytological and histological diagnoses was possible in 226 (38.4%) cases with the cytological diagnosis being concordant with the histopathological diagnosis in 218 (37.1%) cases, giving an overall accuracy of 96.46% [Table 2]. Inadequate smears were obtained in 67 cases. The sensitivity and specificity of FNAC were found to be 95.8 and 97.6% respectively, in the present study.
The pediatric FNAC specimens in the present series were from various body sites, and encompassed a wide range of diagnosis. Our study confirms the conclusion reached by investigators in other adult and pediatric series on FNAC. , We found that FNAC can be useful in diagnosing suspected malignant tumors, sensitivity and specificity rates being 95.8 and 97.6% with no complications occurring in our patients.
Ancillary studies including immunohistochemistry, electron microscopy, cytogenetic studies, flow cytometry, and microbiological culture can be performed on aspirated material. This would enable a more specific diagnosis and provide additional information in some difficult cases, especially PNET (primary neuro-ectodermal tumors) of the thorax, abdominal, and retroperitoneal small round cell tumors,  lymphomas, and undifferentiated sarcomas.
One of the most valuable uses of FNAC is in the assessment of lymphadenopathy in children.  It is one of the most common reasons for performing FNAC in children. In our series, FNA specimens of the lymph node represent the largest group of aspirates in the malignant category (25.1% cases). This is in contrast to a study done by Kusumakumary et al. ,  who found lymphomas to be the third most common malignancy. In our study, there was a slight male preponderance in the lymphoma cases with a median age of 8.7 years. These observations correlate with those of a study conducted by Murphy.  According to Tunkel et al. ,  FNAC of cervico-facial masses is a useful step in diagnosing lymphomas. By FNAC lymph node, one can i) select patients who can preferably be followed clinically, thereby avoiding unnecessary surgery; ii) distinguish lymph nodes from other masses; iii) select the lymph node for excisional biopsy; iv) document recurrence of primary hematopoietic malignancies or metastatic disease, and v) relieve anxiety when lymph node involvement is nonspecific and transient.
Pediatric small round cell tumors constitute a good proportion of malignancies, accounting for 21.3% of the cases in our study, which is the second most common group after lymphomas. These included cases of Ewing's sarcoma (9), retinoblastoma (16), neuroblastoma (16), and intraabdominal desmoplastic small round cell tumor (IADSRCT) (one case); nine cases were unclassifiable.
In cases of Ewing's sarcoma, we found that a useful technique to confirm the diagnosis is a strongly positive PAS stain that is sensitive to diastase treatment. Cytological examination was diagnostic in all cases, along with relevant clinical and radiological backgrounds. Similar views have been expressed by other authors also. , The patients were directly referred for radiotherapy and responded well to the treatment. Fr φstad et al .  observed that FNAC together with immunocytochemistry, is a rapid, physically atraumatic, and accurate method in diagnosing both primary Ewing's family of tumors of bone and soft tissue, as well as cases of relapse.
We observed an interesting and rare case of IADSRCT in a nine year-old male presenting with an epigastric lump.  FNAC yielded hypercellular smears with undifferentiated malignant cells showing nuclear moulding similar to the observations by Gerald et al . 
McGhaey et al .  has emphasized that although FNAC is successful as a diagnostic tool in the pediatric population, confirmatory ancillary studies are essential for proper diagnosis of small round cell tumors due to extensive cytomorphological overlap. An important precaution to be taken especially in intraabdominal tumors is to have an ultrasonography (USG) report, or to preferably perform a USG-guided FNAC, which reveal the exact organ of origin of the tumor; since even an inadverdent FNAC from normal spleen may be interpreted as a small round cell tumor.
Abdominal masses are a frequent presenting complaint in pediatric surgery, and many of them are diagnosed as Wilms' tumor. It was the only renal tumor observed in our study, comprising of 26 cases. FNAC was done in all of them, which revealed varying combinations of blastemal, stromal and epithelial elements. Similar findings have been observed by Beckwith.  Cyto-histological correlation was possible in 24 cases, giving a 92.3% diagnostic accuracy. FNAC is a relative contraindication in primary resectable Wilms' tumors, because of the risk of tumor seeding and rupture of the renal capsule. However, a study initiated by The International Society of Pediatric Oncology,  found that diagnostic needle biopsy, followed by preoperative chemotherapy resulted in a decreased rate of intraoperative tumor rupture and other complications, especially in massive and advanced tumors. This has been corroborated by our study. Removal of the needle tract while doing nephrectomy, also helps to exclude the possibility of tumor seeding.
FNAC is thus an effective method for evaluation of masses in pediatric patients. It need not replace the open surgical biopsy, but can be a valuable tool for screening of palpable as well as nonpalpable masses, and for follow up of patients with a history of malignancy. For its diagnostic potential to be realized however, the clinician must understand the strengths and weaknesses of this procedure, along with the technical limitations.
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