Chondromyxoid fibroma (CMF) is a rare, benign cartilaginous tumor composed of myxoid and fibrous components, accounting for approximately 1% of all bone tumors. It typically arises in the metaphysis of long bones, with epiphyseal involvement of the short tubular bones of the hand and foot being uncommon. We report the case of a 14-year-old girl who presented with pain and a gradually progressive swelling of the left great toe, occurring after a fracture sustained 2.5 years earlier. Radiological findings were suggestive of an aneurysmal bone cyst or giant cell tumor. Fine-needle aspiration cytology (FNAC) revealed hypercellular smears comprising pleomorphic oval to spindle-shaped cells along with dense, pink osteochondroid material; the cytological diagnosis was rendered equivocal, and malignancy could not be excluded. Subsequent histopathological examination showed a well-circumscribed tumor with a lobular architecture composed of alternating hypocellular and hypercellular areas of myxomatous stroma and immature cartilaginous cells, confirming a diagnosis of chondromyxoid fibroma. Although a low-grade tumor, CMF may show nuclear atypia histologically and can mimic chondrosarcoma; distinguishing between the two is of paramount importance to avoid over-diagnosis and unnecessarily aggressive treatment of this benign entity. Complete surgical resection with long-term follow-up remains the mainstay of management, given the relatively high rate of recurrence.

Striated duct adenoma (SDA) is a rare benign salivary gland neoplasm with limited cytologic characterization. We report a case of SDA with cytologic, histologic, immunohistochemical, and molecular correlation to further define its morphologic spectrum and diagnostic considerations. The patient was a 62-year-old male with a submandibular gland mass. Cytologically, the specimen demonstrated loose clusters of monomorphic epithelial cells ranging from cuboidal to rare elongated or slightly spindled morphology, with moderate amounts of variable oncocytic cytoplasm. Nuclei were ovoid and normochromatic with occasional nuclear grooves and infrequent pseudoinclusions. No significant nuclear atypia, mitotic activity, necrosis, or stromal components were identified. Using the 2nd Edition Milan System Classification, the case was categorized as Neoplasm: Benign (Category IVA). Histologic examination confirmed SDA, and next-generation sequencing identified an IDH2 p.R172M mutation. The cytologic and histologic features of SDA overlap with other salivary gland neoplasms, especially those with oncocytic/oncocytoid features. Definitive classification relies on histopathologic correlation and, when available, supportive molecular evidence of an IDH2 mutation.

Fluid overload-associated large B-cell lymphoma (FO-LBCL) is a distinct entity introduced in the 5th edition of the WHO Classification of Hematolymphoid Tumors (2022). It denotes a large B-cell lymphoma confined to one or more serous cavities as effusions, without a solid or nodal mass, in the absence of KSHV/HHV8 (and largely EBV) infection, arising in patients with fluid-overload states. It was previously reported under descriptive terms such as "HHV8-negative primary effusion lymphoma-like lymphoma." We describe two cases illustrating the WHO-HAEM5 diagnostic criteria and the diagnostic and prognostic workup of this entity.

Myeloid sarcoma is a rare extramedullary manifestation of acute myeloid leukemia, and primary involvement of the gastrointestinal tract and uterine cervix is particularly uncommon. Due to its low incidence and nonspecific clinical manifestations, the rates of clinical misdiagnosis and missed diagnosis remain high. Herein, we report two cases of myeloid sarcoma arising at rare sites. Case 1 was a 52-year-old male who presented with acute gastrointestinal obstruction. Intraoperative frozen section favored lymphoma, whereas touch imprint cytology of the tumor cut surface revealed numerous round to oval blasts with scant basophilic cytoplasm, finely granular nuclear chromatin, and small nucleoli, consistent with myeloid blast morphology and suggestive of myeloid sarcoma. Postoperative paraffin pathology confirmed the diagnosis of small intestinal myeloid sarcoma. Case 2 was a 63-year-old postmenopausal female who presented with unexplained vaginal discharge. Cervical liquid-based cytology demonstrated scattered medium-sized cells with finely dispersed nuclear chromatin and small nucleoli. Subsequent immunocytochemistry showed MPO and CD117 positivity, identifying myeloid blasts prior to tissue biopsy. Both cervical biopsy and bone marrow examination confirmed the diagnosis of cervical myeloid sarcoma. Cytological evaluation provided valuable morphological clues at different clinical stages, guided subsequent immunohistochemical workup, and shortened the diagnostic timeline in both cases. These cases demonstrate the cytomorphological features of MS at rare sites, and improving awareness of cytological manifestations of MS at atypical sites is helpful for early diagnosis and timely clinical intervention.

Synovial sarcoma (SS) is a rare and aggressive soft tissue malignancy that is more common in the extremities and has an unusual occurrence in the head and neck region. SS has two main subtypes: biphasic and monophasic. Some rare subtypes include poorly differentiated (round cell), monophasic epithelial, calcifying/ossifying, and myxoid types. Here, we present a rare case of a 61-year-old male with two left-sided neck masses abutting the supraclavicular fossa. One of the masses was present for over a year and gradually increased in size. The second mass was noticed a week before he presented to our institution. The fine-needle aspiration (FNA) specimen consists of tight clusters of monotonous epithelioid cells with scant amphophilic cytoplasm, hyperchromatic ovoid nuclei, increased mitotic activity (up to 6 per 10 HPF), and scattered apoptotic bodies. The tumor cells showed patchy expression for cytokeratins and claudin-4 and demonstrated strong and diffuse expression for TLE and SS18-SSX, consistent with a diagnosis of synovial sarcoma. Deep morphological analysis and targeted immunohistochemical workup can aid in the diagnosis of this rare entity in the head and neck area.

Metastasis of renal cell carcinoma (RCC) to the head and neck region is rare, accounting for approximately 8%-14% of all RCC metastases. The thyroid gland is the most common site of metastasis in this region. However, RCC is known for its ability to metastasize to unusual anatomical sites, including the salivary glands. Approximately 0.1% of metastatic salivary gland neoplasms originate from renal malignancies, and the parotid gland is the most frequently involved site. Metastases to the submandibular and sublingual glands are considerably less common. In this report, we present a 62-year-old male patient who developed submandibular gland metastasis 18 years after undergoing radical nephrectomy for clear cell renal cell carcinoma (CCRCC).