Ameloblastic fibrosarcoma is an uncommon odontogenic tumor composed of a benign epithelial component and a malignant ectomesenchymal component most frequently seen in the third and fourth decades of life. It mainly presents as a painful maxillary or mandibular swelling. Radiographs show a radiolucent mass with ill-defined borders. Radical surgical excision and long-term follow-up are the suggested treatment. We report the case of a 22-year-old female with a 2-month history of an asymptomatic swelling in her left mandible. Examination revealed an exophytic growth measuring 3 × 3 cm extending from the mandibular left first premolar to the second molar. The patient underwent a left hemimandibular resection. Histopathological examination revealed a biphasic tumor composed of inconspicuous islands of benign odontogenic epithelium and an abundant malignant mesenchymal component with marked cellularity, nuclear pleomorphism, hyperchromatism, and moderate mitotic figures with clear margins; one year after the surgical procedure, the patient is clinically and radiologically disease-free.

Defining the histologic variant of thyroid carcinoma is an important clinical implication as their progression, recurrence, aggressiveness, and prognosis differ. Warthin-like variant is one of the rarest histologic variants of papillary thyroid cancer. A 36-year-old female sought consult for assessment of a painless right neck tumor. High-resolution neck ultrasound revealed a right hypoechoic, 1.71 × 1.05 cm thyroid nodule. Ultrasound-guided fine-needle aspiration biopsy report was a Bethesda grade III. Thyroid function tests showed Hashimoto's thyroiditis. The patient underwent right hemithyroidectomy. Microscopically, the tumor was composed of papillae lined by cells with eosinophilic cytoplasm, nuclear chromatin clearing, grooves, and pseudoinclusions and a characteristic lymphoplasmacytic infiltrate of the papillae cores. Extension into the perithyroidal soft tissue and 3 ipsilateral lymph nodes was found to be positive for cancer. Warthin-like variant is an uncommon and relatively unknown variant of papillary thyroid carcinoma that has been usually associated with an excellent prognosis. Interestingly, BRAF mutations have been reported to be present in up to 75% of the patients. It is frequently associated with Hashimoto's thyroiditis and presents unique morphological features that make it recognizable on histologic examination. The cytological diagnosis is difficult to assess due to the overlap in its findings with the classical variant and Hashimoto's thyroiditis.

Cervical carcinoma is the most common malignancy of the female genital tract and represents the second most common malignancy in women worldwide. Histologically 85 to 90% of cervical cancers are squamous cell carcinoma. Osteoclastic giant cell rich squamous cell carcinoma is an unusual histological variant of which only 4 cases have been reported. We present the case of a 49-year-old woman with a 6-month history of irregular vaginal bleeding. Examination revealed a 2.7 cm polypoid mass in the anterior lip of the uterine cervix. The patient underwent hysterectomy with bilateral salpingo-oophorectomy. Microscopically the tumor was composed of infiltrative nests of poorly differentiated nonkeratinizing squamous cell carcinoma. Interspersed in between these tumor cells were numerous osteoclastic giant cells with abundant eosinophilic cytoplasm devoid of nuclear atypia, hyperchromatism, or mitotic activity. Immunohistochemistry was performed; CK and P63 were strongly positive in the squamous component and negative in the osteoclastic giant cells, while CD68 and Vimentin were strongly positive in the giant cell population and negative in the squamous component. The patient received chemo- and radiotherapy for recurrent disease identified 3 months later on a follow-up CT scan; 7 months after the surgical procedure the patient is clinically and radiologically disease-free.

Renal cell carcinoma is the most common malignancy of the kidney in adults. In children, however, it only accounts for an estimated 1.8 to 6.3% of all pediatric malignant renal tumors. Papillary renal cell carcinoma is the second most common type of renal cell carcinoma in children. We present the case of a 12-year-old boy with a 2-month history of abdominal pain, unexplained weight loss, and gross hematuria. Computed tomography revealed a horseshoe kidney and a well-defined mass of 4 cm arising from the lower pole of the right kidney. Microscopically the tumor was composed of papillae covered with cells with abundant eosinophilic cytoplasm and high-grade nuclei with prominent nucleoli. Immunohistochemistry was performed; EMA, Vimentin, and AMACR were strongly positive while CK7, CD10, RCC antigen, TFE3, HMB-45, and WT-1 were negative. Currently, 10 months after the surgical procedure, the patient remains clinically and radiologically disease-free.

Brown tumors are osteolytic bone lesions that occur as a result of persistent hyperparathyroidism. They usually appear late in the natural history of the disease and are currently very rare due to an earlier diagnosis of primary hyperparathyroidism. We present the case of a 53-year-old female with a 2-month history of bitemporal hemianopsia and diplopia. A computed tomography showed an osteolytic bone lesion that involved the sphenoid corpus and clivus. A biopsy was made and the histopathology result was consistent with a brown tumor. The aforementioned location is very infrequent to such tumors, and therefore represented a diagnostic challenge. However, in this case, its association to primary hyperparathyroidism was the clue for the diagnosis. The association of a brown tumor secondary to a parathyroid carcinoma has been seldom reported. This case represents, to our knowledge, one of the few brown tumors described in such location and the first secondary to a parathyroid carcinoma.