Extragonadal germ cell tumors: a fine-needle aspiration biopsy study

Cytopathologic diagnosis of extragonadal germ cell tumors: A 10-year institutional review

BACKGROUND

The occurrence of extragonadal germ cell tumors (EGGCTs), either as primary tumors or metastatic disease, is rare. Forms of cytologic sampling, including fluid analysis, fine-needle aspiration, and/or small-core needle biopsy, have been shown to be reliable methods for the diagnosis of germ cell tumors. This study aims to investigate the utility of cytopathologic techniques in the diagnosis of EGGCTs at the authors' institution.

METHODS

The laboratory information system was queried over a period of 10 years (2012-2022) to identify all cytology cases diagnosed on fluid cytology, FNA, and/or small-core biopsy as germ cell tumors in extragonadal locations. Patient demographics, tumor location, serum tumor marker levels, cytopathologic diagnosis, and follow-up surgical resection data were reviewed and correlated.

RESULTS

A total of 35 cases from 32 patients (all males) were identified. Thirty specimens contained satisfactory material for diagnosis (86%) and five were less than optimal for evaluation (14%). Despite this, all cases had clinically useful cytopathologic diagnoses. A total of 19 cytology cases (16 patients) had follow-up resection specimens available. Of these, 11 patients underwent preoperative chemotherapy. Nine patients showed no evidence of residual tumor and two showed histologic concordance. Of the five patients who did not have preoperative chemotherapy, all showed concordant histologic diagnoses.

CONCLUSIONS

Cytology can provide a reliable, accurate method for diagnosing EGGCTs. The practice of preoperative (neoadjuvant) chemotherapy places an extreme importance on the initial cytopathologic diagnosis because the majority of patients with follow-up resection in this series showed no residual tumor.

Fluorescent in-situ hybridization test performed on cell blocks is useful for establishing germ cell origin of metastatic tumors with unusual clinical presentation

The majority of germ cell tumors (GCTs) are characterized by iso-chromosome 12p (i12p) abnormality. The aim of this study is to review the cytomorphologic features and analyze the utility of i12p fluorescent in-situ hybridization (FISH) test in diagnosing metastatic GCTs primarily evaluated by cytologic techniques in patients without prior history of GCTs. The laboratory information system was queried over a period of 10 years to search for cases where i12p FISH test was requested on cytology material. FISH test was performed using TelVysion 12p telomeric probe and CEP 12 centromere probe on cell-blocks. A ratio of 12ptel/CEP12 signal of 1.4 or greater was considered as positive. Patient demographics, clinical presentation, cytopathologic findings, and follow-up surgical resection data were reviewed and correlated. A total of three cases were identified, all men (age range 31-60 years). Cytologic diagnoses were favor metastatic embryonal carcinoma (Case 1, retroperitoneal fluid FNA), metastatic yolk sac tumor/YST (Case 2, lung mass FNA) and adenocarcinoma, likely representing a somatic-type malignancy (SM) arising from a preexisting GCT (Case 3, retroperitoneal mass FNA). This limited study demonstrated high sensitivity for detecting i12p abnormality by FISH test performed on cell blocks. The cytomorphology of extra-gonadal GCTs varies according to the histologic subtype. Sarcomatoid morphology of YST, SM or mixed GCTs further complicates cytology evaluation. FISH test for detection of i12p performed on cell-blocks is extremely useful in establishing germ cell origin of these metastatic GTCs with unusual cytomorphology and guides management in patients without prior history of GCTs.

A comprehensive review of the "tigroid" background cytological concept: what, when, where and why?

The concept of “tigroid” background is used in cytology to describe a peculiar smear background characterized by the presence of a relatively granular, reticulated material that was described as “foamy, lazy, tiger-striped or astrakhan”. It was used to describe the background seen in smears obtained from seminoma. In addition to seminoma, we now know that it can be present in different tumours, mostly carcinomas and round cell sarcomas. These share with seminoma a cytoplasm with high glycogen content and many times clear cell morphology. The “tigroid” background is seen when smears are air-dried and Romanowsky-based stains are used (May-Grunwald-Giemsa and Diff-Quik stains). It is only seen in fine needle aspiration or intraoperative squashing or scrapping samples, but not in specimens obtained from effusions or liquid-based cytology. Wet-fixed cytologic samples with alcohol or with formaldehyde tend to dissolve the background so it is not usually present in Papanicolaou stained smears. In this review, we discuss tumours in which the “tigroid” background is observed and its potential diagnostic utility and aetiology. It is interesting to remark that except for parathyroid adenoma and adenomatoid tumour all the neoplasms in which this background has been observed are malignant.

Extragonadal germ cell tumors: Not just a matter of location. A review about clinical, molecular and pathological features

Extragonadal germ cell tumors (EGGCTs) are uncommon neoplasms, which arise in anatomical locations other than gonads. The pathogenesis of these neoplasms is still poorly understood and it is a matter of debate if they really represent extragondal primary neoplasms or rather extragondal metastasis from occult gonadal neoplasms. The actual observations suggest that EGGCTs represent a unique entity, so their biology and behavior are substantially different from gonadal counterparts. The diagnosis of EGGCTs is often challenging, and differential diagnosis is particularly wide. Nevertheless, a correct diagnosis is essential for the correct management of the patient. We summarize the state of art about EGGCTs, with particular emphasis on diagnosis and prognosis.

Mediastinal seminoma: a case report with special emphasis on SALL4 as a new immunocytochemical marker

Cytological diagnosis is a valuable method for detection of mediastinal tumors, and recent reports have shown the usefulness of fine-needle aspiration cytology for diagnosis of mediastinal tumors, including germ cell tumors. We report a case of mediastinal seminoma diagnosed intraoperatively by cytological examination of cystic fluid containing tumor cells. An anterior mediastinal tumor with cystic component was incidentally found in a 28-year-old Japanese male. Cytological examination of the cystic fluid at the time of tumor resection showed single and loose aggregates of large round to polygonal cells with large round nuclei, vesicular chromatin and nucleoli, and mild to moderate amounts of PAS-positive cytoplasm admixed with mature lymphocytes. A diagnosis of seminoma was made intraoperatively. On subsequent immunostaining, the tumor cells showed nuclear positivity for SALL4, a recently recognized germ cell marker that, in the appropriate setting, can be helpful to distinguish germ cell tumors from other mediastinal neoplasms, such as malignant lymphoma, thymoma, and thymic carcinoma.

Cyto-morphological features of extramedullary acute megakaryoblastic leukemia on fine needle aspiration and cerebrospinal fluid cytology: A case report

Extramedullary deposits may be the presenting feature of acute myeloid leukemia. An early and accurate diagnosis on cytology will aid in correct patient management. This is especially true for patients with acute megakaryoblastic leukemia (AML M7), where bone marrow aspiration may yield only a dry tap. While cytomorphological features of myeloid sarcoma of other types are well recognized due to its rarity, there are only two case reports discussing the morphological details of megakaryoblastic differentiation on aspiration cytology. We present the case of a 25-year-old patient with extramedullary involvement of lymph node and cerebrospinal fluid by AML M7, describing in detail, the morphological features on aspiration as well as exfoliative cytology.

Aspiration cytomorphology of fetal adenocarcinoma of the lung

Fetal adenocarcinoma (FA) of the lung is an exceedingly rare malignancy. Many patients with the well-differentiated form are relatively young and with the high-grade variant are older. We describe the cases of 4 women with FA examined by fine-needle aspiration biopsy. Aspirates were moderately cellular with malignant, mostly aggregated cells. Glands and acini were present. The columnar neoplastic epithelial cells had homogeneous round nuclei with fine chromatin, smooth membranes, and indistinct nucleoli. With the rapid Romanowsky stain, subnuclear vacuoles were evident in some tumor cells; at times, this was associated with a focal extracellular tigroid pattern. Morule formation was present in the 3 specimens. Immunochemically, all tumors manifested epithelial and neuroendocrine differentiation. Cytomorphologic attributes included the following: (1) distinct subnuclear vacuoles, sometimes with an associated tigroid picture; (2) small, uniform, round nuclei; (3) morules; and (4) neuroendocrine differentiation in glandular epithelial cells.

Fine-needle aspiration cytology of thymic basaloid carcinoma: Case studies and review of the literature

We report the features in fine-needle aspiration biopsy (FNAB) of thymic basaloid carcinomas. This is a rare neoplasm, of which there are only three documented in our hospital files. To the best of our knowledge, this is the first fine-needle aspiration (FNA) report on basaloid carcinoma of the thymus. This is a tumor in which the FNA diagnosis is difficult and the differential diagnosis is broad. We describe the cytologic features encountered in the three cases, and immunohistochemical and ultrastructural findings so as to raise awareness of this entity in the differential diagnosis of thymic neoplasms on FNABs. The cases studied included three male patients, aged 73, 65, and 50, who presented with anterior mediastinal masses, with no primary tumor elsewhere. FNAB was performed on two cases, followed by thymectomy. One case, additionally, had metastasis to a cervical lymph node, and the other two were associated with thymic cysts. The diagnoses on all three cases were thymic basaloid carcinoma.

Clear-cell adenocarcinoma of the female genital tract: Presence of Hyaline stroma and tigroid background in various types of cytologic specimens

Hyaline basement membrane-like stromal material and tigroid background are distinctive cytologic features observed in Diff-Quik (DQ)- or Giemsa-stained smears of clear-cell adenocarcinoma (CCA) of the female genital tract. However, it is uncertain how often these features are present in different types of cytologic specimens, and which type of preparation is optimal for this diagnosis. We therefore reviewed the cytologic features of CCA in three types of specimens, including 15 scrape cytology specimens, 7 fine-needle aspiration (FNA) specimens, and 15 peritoneal cytology specimens, with emphasis on the features observed in DQ-stained smears. The cell morphology in scrape cytology specimens and FNA specimens was comparable, whereas in peritoneal cytology specimens, the cytoplasm was better preserved. Most tumor cells had fragile cytoplasm containing variable amounts of fine vacuoles, and round nuclei with distinct or prominent nucleoli. Hyaline stroma was present in 93% of scrape cytology specimens, 71% of FNA specimens, and 80% of peritoneal cytology specimens. Tigroid background was observed in 47% of scrape cytology specimens, 43% of FNA specimens, but in none of the peritoneal cytology specimens. Formation of a tigroid background may be prevented by the abundant fluid content in peritoneal cytology specimens. Hyaline stroma and tigroid background were uncommonly seen in scrape smears from other types of primary ovarian tumors, mainly juvenile granulosa cell tumor and yolk sac tumor. However, the additional presence of papillary structures allows CCA to be readily distinguished from these other tumors. We propose that scrape cytology offers the best approach for the intraoperative cytologic diagnosis of CCA.

Fine-needle aspiration biopsy of nonteratomatous germ cell tumors of the mediastinum

We assessed the usefulness of fine-needle aspiration biopsy (FNAB) in the diagnosis of mediastinal germ cell tumors (GCTs). In the archives of 3 pathology departments, we found records of 7 patients with mediastinal GCTs who underwent mediastinal FNAB as part of the diagnostic workup. The FNAB smears, results of the immunocytochemical analysis, the corresponding histologic findings, and the clinical charts were reviewed. All patients were men (age range, 24-44 years; mean, 32 years). One patient had a history of testicular mixed GCT 10 years earlier. The 6 primary mediastinal GCTs consisted of 3 seminomas and 3 yolk sac tumors. Based on the cytologic features and immunocytochemicalfindings, a cytologic diagnosis of GCT was made in 5 cases, including the case of metastatic GCT In 2 cases, the differential diagnosis was between poorly differentiated carcinoma and GCT Results of ancillary studies were noncontributory in 1 case, and the aspirate of the second case demonstrated extensive necrosis. Our findings demonstrate that a diagnosis of mediastinal GCT, primary or secondary, can be established with a high degree of accuracy on the basis of FNAB. Immunocytochemical analysis helps confirm the diagnosis.

Fine-needle aspiration biopsy of the retroperitoneum: a series of 111 cases not including specific organs

We report on our experience in fine-needle aspiration (FNA) biopsy of the retroperitoneum: 111 FNA biopsies performed on 99 patients. Cytologic diagnoses were divided into four groups: nondiagnostic (unsatisfactory samples because of a low cellularity and/or improperly prepared smears) aspirates (20%), benign (16%), suspicious for malignancy (13%), and malignant (50%). There were no known false-positive samples. We had two false-negative diagnoses due to sampling errors. Among diagnostic smears, the procedure showed a sensitivity of 97% and a specificity of 100%. The predictive value of a positive result was 100% and the predictive value of a negative result was 90%. The overall accuracy was 98%. Metastatic carcinomas accounted for the largest number of lesions in the group of malignant tumors. A primary tumor site was known for the majority of the cases before the aspiration was performed. In the remaining cases we were unable to suggest an origin. It is therefore important to emphasize the role of ancillary studies in patients that are at the first assessment of the disease or when a second intercurrent malignancy is suspected. In our limited experience, a suggestion of the correct subtype of retroperitoneal sarcoma was not possible. As in the rest of cytopathology, a multidisciplinary approach is mandatory in this setting to improve patient management.

Fine needle aspiration (FNA) of testicular germ cell tumours; a 10-year experience in a community hospital

A retrospective reappraisal is made of the smears of 29 testicular germ cell tumors (TGCT) studied by FNA in which both orchiectomy specimens and histologic diagnoses were available. In 22 cases (75.86%) the yield was sufficient and contained cells suitable for cytologic diagnosis; in these 22 cases a diagnoses of malignancy was reached. In four cases (13.79%) the yield was sparse and a diagnostic cells were partially obscured by haemorrhage and necrosis; these cases were categorized as suspicious of malignancy. In these cases (10.34%) the yield was not suitable for cytologic evaluation because haemorrhage and necrosis hampered evaluation of diagnostic cells. The cytologic findings that enable a reliable diagnosis of TGCT are described and those cytologic features that may lead the less experienced cytopathologist into an erroneous diagnosis are discussed. Pure TGCT can be confidently diagnosed with FNA and mixed TGCT can be successfully diagnosed, although it is difficult to recognized every cytologic subtype observed in the histologic sections. Despite the advantages of FNA for the prompt diagnosis of TGCT, FNA can not fully replace the histologic diagnosis and should rather be considered as a helpful tool in the work-up of testicular tumours.

Is it feasible to diagnose germ-cell tumors by fine-needle aspiration biopsy?

Fine needle aspiration biopsy is an extremely useful procedure for the diagnosis of germ cell tumors. Most of the subtypes can be easily recognized and differentiated from other subtypes. For difficult cases clinical pathologic correlation may be extremely helpful in establishing a precise diagnosis. Mixed germ cell tumors may cause some difficulty if one of the components is predominant. Immunohistochemistry may also play an important role in arriving at a definitive diagnosis.

Differential diagnostic considerations and potential pitfalls in fine-needle aspiration biopsies of the mediastinum

The mediastinum is the host for a number of relatively unusual primary neoplasms, as well as a frequent recipient of metastatic tumors. From the perspective of fine-needle aspiration cytomorphology, several distinct patterns are yielded. The polygonal (or epithelial-like) cell pattern may be seen with benign and malignant thymomas, germinomas, embryonal carcinoma, and many metastatic carcinomas. An intimate admixture of small lymphocytes with these epithelial cells may occur in this category. The small cell pattern may be produced by malignant non-Hodgkin's lymphomas, neuroblastoma, carcinoid tumors, and metastatic oat cell carcinoma. Uncommon morphologic forms of thymoma and carcinoid tumors, as well as benign mesenchymal lesions, may yield a picture of a spindle-cell proliferation. In addition to cytomorphology, the cytologist needs to integrate clinical, radiographic, immunocytochemical, and ultrastructural data to formulate a final diagnosis.