Background : Endometrial dedifferentiated carcinoma (EDC) is a rare tumor that contains an admixture of undifferentiated carcinoma cells with unclear differentiation grade and low-grade endometrial carcinoma. Herein, we present a case of EDC in which the undifferentiated component was recognized in cytological specimens of the cervix, and both the differentiated adenocarcinoma and undifferentiated components were recognized in cytological specimens of the endometrium.

Case : The patient was a woman in her 60 s, in whom pelvic imaging revealed an intrauterine solid mass (measuring 8 cm in diameter) and enlarged pelvic lymph nodes. The tumor was diagnosed as a uterine carcinoma based on the cytological and histopathological findings of the endometrium, and surgical resection was performed. Microscopically, the tumor consisted of a low-grade endometrioid carcinoma component and an undifferentiated carcinoma component. Immunohistochemically, the undifferentiated atypical cells showed diffusely positive staining for vimentin, while a small proportion of the cells also showed positive staining for CK18 and EMA ; based on the findings, the tumor was diagnosed as an EDC. Contrast-enhanced computed tomography performed after surgery revealed multiple metastatic lesions in the pelvic lymph nodes, liver, and lungs. On day 55 after surgery, the patient died of multiple-organ failure.

Conclusion : EDC is an extremely malignant tumor, and carries a poorer prognosis than FIGO G3 endometrioid adenocarcinoma. A salient feature of endometrial cytology in cases of EDC is that both well-differentiated and undifferentiated carcinoma cells can be recognized.

Background : Placental site trophoblastic tumor (PSTT) is a rare gestational trophoblastic neoplasm. Few reports so far have described the cytological findings of PSTT. Herein, we report a case of PSTT in which the endometrial cytology findings suggested the diagnosis of PSTT.

Case : The patient was a woman in her 30s, who had delivered her second child a year before. She visited our hospital with a one-month history of discomfort around the vaginal orifice. We found and resected a polypoid lesion in her vaginal wall. Histologically, scattered isolated intermediate trophoblasts were observed. A semiquantitative evaluation of the urinary human chorionic gonadotropin level revealed a mild increase of the level, and a trophoblastic disease was suspected. Magnetic resonance imaging revealed an ill-defined tumor on the right anterior wall of the uterine corpus. Endometrial cytology preparations showed rounded and frequently binucleated cells with thick cytoplasm. The nuclear chromatin was fine and uniform. There was no thickening of the nuclear margin, and the nucleoli were not conspicuous. No necrotic or hemorrhagic material was found. Immunocytochemically, many of these cells showed positive staining for human placental lactogen. Thus, they were regarded as cells of intermediate trophoblast origin, and PSTT was strongly suspected. The patient was transferred to a university hospital, and total hysterectomy was performed. The final histopathological diagnosis was PSTT.

Conclusion : We encountered a rare case of PSTT, in which intermediate trophoblasts were observed in endometrial cytology preparations. In the case reported herein, endometrial cytology proved to be a significant aid to the diagnosis of PSTT.

Background : Pancreatic adenosquamous carcinoma (PASC) is a malignant tumor consisting of both adenocarcinoma (AC) and squamous cell carcinoma (SCC) components. Since both components are rarely observed at the same time in cytological smears, cytological diagnosis is often difficult. Herein, we report a case of PASC in which both the AC and SCC components could be confirmed in the tumor using liquid-based cytology (LBC).

Case : The patient was a man in his 60 s who was detected to have a mass in the head of the pancreas while receiving chemoradiotherapy for esophageal cancer. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy was performed, and a squash preparation of the specimens revealed both clusters of atypical cells, and a small component of SCC cells with keratinization. Both the SCC and AC components were confirmed by LBC. The SCC component showed positive immunocytochemical staining for p40, and the tumor was suspected as a PASC. In the resected specimen, the tumor was composed of an AC component with clear formation of glandular structures and an SCC component with cells showing an irregular alveolar growth pattern ; based on these findings, the tumor was confirmed as a PASC.

Conclusion : Understanding the cytological characteristics of AC and SCC is important for the diagnosis of PASC. In addition, the use of LBC with high quality cell collection by EUS-FNA and immunocytochemistry for p40 are useful for confirming the non-keratinized SCC component.

Background : Mammary secretory carcinoma is an extremely rare malignant tumor classified as a specific type of breast cancer, that accounts for less than 0.1% of all breast cancers. In this article, we present the findings of fine needle aspiration cytology (FNAC) in a case of mammary secretory carcinoma.

Case : A woman in her 60 s visited our hospital complaining of right chest pain. Examination of stained FNAC specimens revealed red-purplish material that looked like mucus secreted by the epithelium and deeply-staining lipid droplets in a light-green background. The tumor was composed of an abundance of small polygonal cells arranged in small clusters or scattered singly, lacking the two-cell pattern, together with blood vessels. Mucous globular structures (MGS) containing spherical mucus-like material were observed in some intercellular spaces and in the cytoplasm. The cytoplasm was broad and granular, containing some large or small vacuoles, and the cells showed mild nuclear atypia.

Conclusion : These findings suggest that the most useful approach for the differential diagnosis of mammary secretory carcinoma may be to look for the presence/absence of extracellular material, their properties, and the cell arrangement.

Background : Rhabdomyosarcoma (RMS) of the urinary bladder is rare in adults, accounting for less than 0.5% of all bladder tumors.

Case : A 70-year-old man presented to us with the chief complaint of gross hematuria, and abdominal computed tomography (CT) revealed a neoplastic lesion protruding outside the bladder. Urinary cytology and transurethral resection of the bladder tumor (TURBT) confirmed the diagnosis. Urinary cytology showed numerous atypical cells in a necrotic and inflammatory background. The atypical cells appeared as single cells or in small compact clusters ; the N/C ratio was high, with the nuclei being markedly enlarged and containing coarse and granular chromatin. Cytological diagnosis suggested the possibility of high-grade urothelial carcinoma, small cell carcinoma, or malignant lymphoma. Immunocytochemical staining of a cell block specimen showed positive staining of the atypical cells for myogenic markers including desmin and myogenin, and for neuroendocrine markers, including synaptophysin and CD56. The tumor cells showed negative staining for known markers of urothelial carcinoma, including cytokeratin, GATA3, and p63. Histological examination of the TURBT specimen showed sheet-like proliferation of atypical cells with hyperchromasia and nuclear molding. Immunohistochemical staining showed results similar to those of staining of the cell block specimen, and we confirmed the diagnosis of primary RMS of the bladder.

Conclusion : Urinary cytology combined with immunohistochemical staining of a cell-block specimen can provide a highly accurate cytological diagnosis of adult-onset RMS.

Background : We report a case of diffuse large B-cell lymphoma (DLBCL) arising in the renal pelvis, that was misdiagnosed by preoperative urinary cytology as invasive urothelial carcinoma, lymphoma-like/plasmacytoid variant (PUC).

Case : The patient was a man in his 60 s who was suspected as having a left renal tumor and referred to the urology department of our hospital. Urinary cytology showed scattered small tumor cells with round nuclei in an inflammatory background. The tumor cells showed a high N/C ratio and the nuclei contained fine granular chromatin. A few atypical cells were also seen, with irregular nuclei and prominent nucleoli. Based on these cytological findings, we diagnosed the tumor as PUC.

Histopathological examination of the excised kidney specimen revealed a diffuse proliferation of tumor cells with round nuclei in the subepithelium of the renal pelvis. The tumor cells were round and mononuclear, had a high N/C ratio and irregular nuclei containing prominent nucleoli, and lymphocytes and plasma cells were admixed with the tumor cells. Based on the above histological findings and results of immunostaining, we diagnosed the tumor as a DLBCL.

Conclusion : Primary renal lymphoma is a very rare tumor, and it is difficult to distinguish DLBCL from PUC by urinary cytology alone. However, this tumor should be borne in mind in cases showing atypical cells in clusters, with irregular and constricted nuclei, and polymorphic cell diameters.

Background : We report a case of dedifferentiated liposarcoma arising from the neck that directly invaded the thyroid gland.

Case : A 60-year-old man consulted a local hospital with the chief complaint of hoarseness of the voice. He was suspected as having a thyroid tumor, and was referred to our hospital. Imaging revealed a mass in the posterior pole of the left lower lobe of the thyroid gland that was suspected as being a malignant thyroid tumor. Invasion of the trachea and esophageal wall was suspected. Fine needle aspiration cytology revealed bundled aggregates of spindle-shaped cells with a high N/C ratio. In addition to the spindle-like cell shape, diverse nuclear shapes were found, including large round nuclei. The nuclear chromatin was delicate, and the nucleoli were inconspicuous, suggestive of sarcoma. The left thyroid lobe, surrounding tissue, and cervical lymph nodes were also dissected. Histological examination revealed proliferating spindle-shaped cells with swollen rod-shaped nuclei, intertwined in spirals or bundles. Nuclear atypia was prominent, and numerous mitotic figures were observed. Atypical adipocytes were found in the surrounding tissue, and the cells showed positive immunostaining for MDM2 and CDK4. We thus diagnosed the patient as having dedifferentiated liposarcoma in the soft tissues surrounding the thyroid gland.

Conclusion : Dedifferentiated liposarcoma should be considered in the differential diagnosis when spindle-shaped cells are identified on thyroid gland aspiration cytology.

Background : Intraductal carcinoma (IDC) is a rare salivary gland tumor with a good prognosis.

Case : The patient was a man in his seventies who presented to us with a 10-year history of a small left parotid mass that had started to increase in size approximately one year ago. MRI revealed a 50-mm multilocular cystic mass caudally over the inferior pole of the left parotid gland, and fine-needle aspiration cytology (FNAC) was performed. The FNAC specimen revealed a mildly overlapping epithelial mass in a background of lymphocytes, neutrophils, and macrophages phagocytosing hemosiderin. The nuclei of the tumor cells were relatively small and mildly atypical, with granular chromatin and one or two small nucleoli. The tumor cells contained greenish and vacuolated cytoplasm and intracytoplasmic lumina containing secretions as well as brownish-red granules. Since the cytological findings suggested a low-grade malignant lesion, we categorized the findings as “suspicion for malignancy, low grade” according to The Milan System for Reporting Salivary Gland Cytopathology, with the differential diagnosis including secretory carcinoma and low-grade adenocarcinoma (cystadenocarcinoma).

Conclusion : IDC may be cytologically similar to secretory carcinoma and low-grade adenocarcinoma (cystadenocarcinoma), which may pose difficulties in accurate estimation of the histological type. However, since IDC has a more favorable prognosis than other malignant salivary gland tumors, it is important to confirm the low-grade malignant nature of the tumor by FNA before surgery.

Pulmonary granular cell tumor (GCT) is a rare tumor derived from Schwann cells. Herein, we report a case of pulmonary GCT, in which intraoperative imprint cytology contributed to the diagnosis. Imaging showed a tumor in the right upper lobe of the lungs. Bronchoscopy revealed bronchial obstruction of the right B². No tumor cells were detected in the bronchial washings or on brushing cytology. Right upper lobectomy was performed. Based on the coarsely granular cytoplasm without nuclear atypia observed on intraoperative imprint cytology, GCT was strongly suspected. With a good knowledge of cytological characteristics, GCT may be diagnosed by careful cytological examination.