Melanotrichoblastoma: a rare pigmented variant of trichoblastoma.

Trichoblastomas are rare cutaneous tumors arising from the hair bulb and mesenchyme. Although they are benign, they can pose a diagnostic dilemma for the clinician and pathologist because they clinically and histologically mimic more common lesions such as basal cell carcinomas (BCCs) and trichoepitheliomas. It is important for the clinician and pathologist to be aware of such tumors and their variants. We present a case of a melanotrichoblastoma, an exceedingly rare variant of trichoblastoma, as well as review the current literature on the clinical presentation and histologic differentiation of these unique tumors with their more commonly seen mimics.

Malignant paraganglioma of the bladder: a case report and review of the literature.

Although paragangliomas of the bladder are uncommon, malignant paragangliomas of this anatomic site are exceedingly rare, with a mere 37 previously reported cases. We report the case of a 58-year-old man with a malignant paraganglioma of the bladder who sought care secondary to gross hematuria; however, misdiagnosis of this tumor resulted in hypertensive crisis during cystoprostatectomy. Not only does this case present a unique malignant paraganglioma of the bladder, but also it discusses the clinical ramifications when misdiagnosed. Like pheochromocytomas, extra-adrenal paragangliomas can manifest with similar sympathetic stimulation; this becomes a serious complication for clinicians resecting these tumors in unusual locations without proper histologic diagnosis. Additionally, we discuss the unique clinical and pathologic findings of our patient and comprehensively review the previously published cases comparing clinical and pathologic features. Several interesting findings are identified including average age at diagnosis, gender predilection, presenting symptoms, size at diagnosis, and common sites of metastasis.