The cytology of pediatric masses: a differential diagnostic approach

Some general considerations about the clinicopathologic aspects of soft tissue tumors in children and adolescents

Soft tissue tumors in children and adolescents are an important group of neoplasms, pseudoneoplasms, and tumefactive malformations with some distinctive clinicopathologic, genetic, syndromic, and therapeutic implications. In addition to the basic pathologic examination, there is the availability of diagnostic adjuncts in various settings based upon the histopathologic features that facilitate and/or corroborate a diagnosis. Immunohistochemistry, cytogenetics, molecular genetics, and an ever-increasing array of new technologies are available to address specific diagnostic questions and even potential therapeutic strategies. This review focuses upon some of the unique aspects of soft tissue tumors in children, including the classification, approach to the diagnosis, grading, clinical and pathologic staging, therapy-related changes, pathogenesis, and risk factors.

Cytological evaluation of head and neck tumors in children—A pattern analysis

A total of 135 pediatric head and neck tumors diagnosed in our institute were reviewed with a view to elucidate the overall cytological patterns and analyze the important cytological features. Ninety-four tumors (69.6%) were aspirated for a primary diagnosis, and in 41 (30.4%) cases, fine-needle aspiration cytology was performed to document relapse, recurrence or a metastasis. Among the 94 tumors aspirated for a primary diagnosis, 66 cases (70.2%) were accurately diagnosed, in 22 cases (23.4%) a broad working diagnosis was offered, and 6 cases (6.4%) were misdiagnosed. The accuracy rate was higher (79.3%) when relapse-recurrent and metastatic tumors were included. The smears were broadly divided into six patterns, viz. round cell, epithelial, anaplastic, giant cell, mixed inflammatory, and spindle cell patterns. The round cell pattern was the most frequent one encountered in this group. The cytological features that stood the test of variability were lymphoglandular bodies and a noncohesive cell population in hematolymphoid malignancies, pale chromatin and cytoplasmic vacuoles in primitive neuroectodermal tumor/Ewing's sarcoma (PNET/ES), neuropil and rosettes in neuroblastoma, and plasmacytoid rhabdomyoblasts in rhabdomyosarcoma. A fairly good accuracy was seen in the diagnosis of metastatic undifferentiated carcinoma and anaplastic lymphoma, but the giant-cell and spindle-cell tumors continued to pose a problem in diagnosis. Ancillary techniques such as immunocytochemistry and electron microscopy applied in limited cases helped evaluate Langerhans cell histiocytosis, alveolar rhabdomyosarcoma, and the PNET/ES family of tumors.

Fine-needle aspiration biopsy in pediatric oncology patients: a review of experience with 829 patients (899 biopsies)

The authors review their 20-year (1985-2004) experience with fine-needle aspiration biopsy (FNAB) in 829 children (all but 1 younger than 18 years), from whom 899 samples were obtained. All patients presented with clinical data suggesting malignancy. The procedure followed standard methods (22- to 24-gauge needle; mean of six alcohol-fixed and/or air-dried, H&E- or Giemsa-like-stained smears/procedure; leftover clots processed as a biopsy). Interpretation of cytologic smears was performed taking into consideration the clinical, laboratory, and imaging data. Smears diagnosed as positive for malignant cells were reported in 510 samples (56.7%) (463 patients); 1.89% of the smears were found inadequate for diagnosis. Positive for malignancy cases included 467 primary tumors, 52% of which were localized to the abdomen. NMYC status was determined on neuroblastoma samples by fluorescent in situ hybridization. Overall sensitivity of the procedure was 98% (500/510 FNAB); specificity was 92.6% (463/500 FNAB); positive predictive value was 1 and negative predictive value was 0.99. All FNABs diagnosed as benign tumors or inflammatory lesions correlated with histology and/or clinical outcome. FNAB proved to be highly cost-effective, avoiding a surgical biopsy. The procedure was found to be extremely helpful when deciding on preoperative chemotherapy.

Changing role of fine-needle aspiration in the evaluation of pediatric masses

This study examines changes in the use of fine-needle aspiration (FNA) in the pediatric population in the past 14 yr at the University of California, Davis Medical Center. Pediatric FNAs from two 7-yr periods were compared regarding percentage of satisfactory cases and cases with a previous history of cancer, sensitivity, specificity, type of general diagnostic category, ratio of benign to malignant diagnoses, and sources of diagnostic error. Changes in the later 7-yr period included decrease in the percentage of round cell lesions with an increase in spindle cell and epithelial/epithelioid lesions, fewer patients with a prior history of cancer, and a marked increase in benign to malignant ratio. These changes illustrate that FNA is being used more commonly in the general pediatric population, and that the types of lesions seen in this population are not very dissimilar to those seen in adults.

Work-up and diagnosis of pediatric non-Hodgkin's lymphomas

Non-Hodgkin's lymphomas (NHL) in children and adolescents represent about 10% of childhood cancers. Although the types of NHL commonly seen in this population are relatively limited to lymphoblastic lymphomas, Burkitt's and Burkitt-like lymphomas, and large cell lymphomas, correct diagnosis and classification are essential for optimal therapy. Careful handling of pathologic specimens, along with collection of proper materials for ancillary studies such as immunophenotyping, cytogenetics, or molecular studies, will aid the pathologist in reaching a correct diagnosis. Specific morphologic, immunophenotypic, and genetic features of the commonly seen types of pediatric NHL are described.

Cytologic diagnosis and subtyping of rhabdomyosarcoma

We reviewed the cytological findings of 38 cases of rhabdomyosarcoma (RMS) with histological confirmation performed during a period of 15 years and proposed a morphological subtyping based on the most prominent cytologic features. Seventeen of these cases were alveolar, 14 cases embryonal, and seven botryoid subtypes. From these cases, a total of 43 samples, of which 37 were fine needle aspiration (FNA) biopsies and six were touch imprints, were evaluated. Detailed cellular features were identified which enabled differentiation into histological subtypes. In the alveolar RMSs, most tumour cells were small and lymphocyte-like, having finely granular chromatin. The finding of cells with more abundant cytoplasm, eccentrically located nuclei and bi/multinucleated tumour cells in a background of mucosubstance helped in the differential diagnosis. Two cell types, including large, tadpole or ribbon-shaped tumour cells and small, round cells with scant cytoplasm, were seen in embryonal RMSs. In botryoid RMSs, a cell type with tightly grouped nuclei within elongated cytoplasm similar to a myotubular structure was observed in addition to the two cell types of embryonal RMSs. We conclude that with experience it will be possible to subtype these tumours by cytologic examination alone.

Fine-needle aspiration of breast masses. A review of its role in diagnosis and management in adolescent patients

PURPOSE

To assess the role of fine-needle aspiration biopsy (FNA) in the evaluation and management of breast masses in adolescents.

METHODS

All FNAs performed on organ masses over a 15-year period on patients age 21 years and younger were evaluated. Cases were collected from four large university-affiliated teaching hospitals and clinics. Pathology records from the laboratory information systems were reviewed. Data included clinical information, anatomic site, and cytologic diagnoses. Surgical follow-up was included when available.

RESULTS

Three hundred and twenty-five FNAs from 302 patients were reviewed. Of 325 aspirates, 59 were breast FNAs (in 51 patients: 4 males and 47 females). Among all organs, the breast was the most common one aspirated in females. Of the breast aspirates in females, 49% were diagnosed as fibroadenomas. No cases of malignant breast disease or phyllodes tumors were encountered. Surgical biopsy follow-up was available in 23.7% of the patients. Of those masses which were subsequently surgically biopsied, most were diagnosed as either fibroadenoma (11) or juvenile fibroadenoma (two). One other case biopsied showed ductal hyperplasia and adenosis. The majority of the remaining cases were followed up clinically, since the clinical nature and cytologic features of the lesions were those of fibrocystic changes or benign cysts.

CONCLUSIONS

In the series of FNAs we examined, breast masses were the most frequent lesions aspirated in adolescent females, with fibroadenomas being the most common lesion encountered. FNA proved to be a useful and reliable tool in the evaluation and management of masses involving the adolescent breast. The majority of breast masses in adolescents are benign, and lesions can be managed conservatively in this age group. The use of noninvasive diagnostic procedures such as FNA and ultrasound can reduce the need for open surgery during breast development.

Fine-needle aspiration cytology of sarcoma: retrospective review of diagnostic utility and specificity

Fine-needle aspiration cytology (FNA) is useful because of its low cost, quick turn around time, and low incidence of complications. This study investigates the role FNA plays in the evaluation of sarcoma. We reviewed all the pathologic material from patients with sarcoma or a FNA diagnosis suggestive of sarcoma at the University of California-Davis Medical Center (1985-1994). Fifty-two of 196 patients identified (26.5%) were evaluated with FNA exhibiting 46 soft tissue and 6 bone lesions located in the extremities (19), trunk (19), head and neck (8), retroperitoneum (3), and abdominal cavity (3). Among 196 patients identified, those evaluated by FNA had soft tissue rather than bone lesions (P < .001) and primary sites other than in the extremities (P < .001). The primary neoplasms for the 52 FNA patients included 47 sarcomas (10 malignant fibrous histiocytomas and 16 other types), 1 intramuscular myxoma, 2 lymphomas, and 2 spindle cell (sarcomatoid) carcinomas. In 43 patients (22% of total), FNA was used first, before a primary diagnosis. The FNA report showed the correct specific neoplasm in only 20.9%. However, the FNA reports reflected an effective positive diagnosis leading to appropriate diagnostic biopsy in 88.4%, while only 7.0% were misleading (benign or inflammatory) and 4.6% inadequate. Review of FNA slides for 32 of 43 patients in which FNA was used first, in a blinded fashion, exhibited 21.9% specificity for the specific neoplasm, and 88.4% effective positive diagnoses. In 9 patients, FNA was utilized to investigate recurrence. Five out of 5 instances of recurrent sarcoma were identified by FNA. However, FNA misidentified recurrence in 3/4 instances, exhibiting suspicious cells from regenerating skeletal muscle (2) and a traumatic neuroma (1). The specific diagnosis for sarcomas is challenging even with surgical material. FNA usually does not provide a specific diagnosis (only in 20.9% of cases) and review of routinely prepared slides showed the same specificity as reflected by the original FNA report, at times formulated with the benefit of immunohistochemistry or electron microscopy. FNA effectively evaluated lesions in 45 of 52 patients (86.5%), confirming the useful screening role for this technique in sarcomas.

Fine-needle biopsy of pediatric lesions: a three-year study in an outpatient biopsy clinic

Diagnostic Cytology Laboratory, Inc., has an outpatient Fine Needle Biopsy Clinic, which evaluated 7,487 fine-needle biopsies (FNB) from January 1989 to February 1992. Two hundred eighty-eight (3.8%) of these specimens were collected from patients 19 years old or younger and this represents the largest study of this population in the scientific literature. The majority of these specimens were obtained from palpable masses in the head and neck region [lymph nodes (58.3%), thyroid (7.6%), and salivary gland (5.2%)] while a smaller number were collected from miscellaneous soft tissue (18.8%) and breast masses (10.1%). Thirteen (4.5%) (from 12 patients) were diagnosed as malignant by FNB and 275 (95.5%) (264 patients) were benign by FNB. This benign:malignant ratio (22:1) is significantly higher than has been reported from tertiary care institutions and is a reflection of the difference of this outpatient population. Two hundred nine of 276 patients (75.7%) had adequate follow-up, including 137 (49.6%) patients followed by observation, 48 (17.4%) patients followed by surgical biopsy, and 24 (8.7%) patients followed by some other modality: imaging studies, flow cytometry, or treatment. There was a single false positive diagnosis (a pilomatrixoma) and one (1) false negative interpretation (a cystic acinic cell carcinoma) resulting in a diagnostic sensitivity of 92.3% and a specificity of 99.6%. The positive predictive value was 92.3%, the negative predictive value was 99.6%, and the test efficiency was 99.3%. The utility, cost-effectiveness and uniqueness of the clinic population is discussed.

Lymphoglandular bodies in lymphoid lesions and non-lymphoid round cell tumours: a quantitative assessment

Lymphoglandular bodies (cytoplasmic fragments) were counted in 10 high power fields (HPF) of the smears in 35 cases of non-Hodgkin lymphoma (NHL), 26 Hodgkin's disease (HD), 36 reactive lymphadenitis, 24 non-lymphoid round cell tumors, and 20 cases of secondaries in lymph nodes. The number of lymphoglandular bodies in both May-Grünwald-Giemsa (MGG) and hematoxylin-eosin (H&E) stained smears in NHL, HD, and reactive lymphadenitis were significantly higher compared to non-lymphoid round cell tumors (P < 0.001). In H&E stained smear 92.5% of NHL, 86.2% of reactive lymph nodes, and 66.7% of HD cases had > 100 lymphoglandular bodies per 10 HPF. In MGG stained smears 100% NHL, 89.7% of reactive lymphadenitis, and 66.7% of HD cases contained > 100 lymphoglandular bodies per 10 HPF. On the other hand only 4.8% of non-lymphoid round cell tumors crossed this level in both H&E stained and MGG stained smears. Number of lymphoglandular bodies was also significantly higher in MGG stained smears compared to H&E stained smears (P < 0.05 to < 0.01) and in fine-needle aspiration (FNA) smears compared to imprint smears (P < 0.01 to < 0.001) in cases of NHL, HD, and reactive lymphadenitis.

Fine-needle aspiration diagnosis of intra-thoracic and intra-abdominal lesions: review of experience in the pediatric age group

Review of fine-needle aspiration (FNA) smears from 121 pediatric patients with intra-thoracic and intra-abdominal lesions revealed 42 (34.7%) cases of neoplasms, 35 (28.9%) cases of tuberculosis, 12 (9.9%) cases of non-tuberculous inflammations, 4 (3.3%) cases of benign cystic lesions, and 28 (23.1%) inadequate/inconclusive cases. The age of the patients ranged from 20 days to 18 yr. Ultrasound and/or CT study done in 105 cases localized the lesions in following common sites: lungs (19 cases), mediastinum (22 cases), liver (14 cases), intestines (11 cases), and lymph nodes (17 cases). The neoplastic lesions consisted of 39 malignant, one suspicious, and two benign neoplasms. Among the neoplasms, the small round cell tumors were the most frequent (27 cases), followed by germ cell tumors (eight cases) and miscellaneous neoplasms (seven cases). The common small round cell tumors were non-Hodgkins lymphoma (eight cases), hepatoblastoma (seven cases), neuroblastoma (five cases), and nephroblastoma (three cases). A combined clinical, imaging, and FNA cytology approach was found to be useful in arriving at a tissue diagnosis.