Angiosarcoma of the Scalp Mimicking an Inflammatory Scarring Alopecia and Diagnosed on Horizontal Histologic Sections.

While most forms of alopecia neoplastica are attributable to cutaneous metastases from visceral primary malignancies, rarely a diffuse primary skin cancer may present as alopecia. Herein, we present a case of angiosarcoma which clinically mimicked an inflammatory alopecia and was diagnosed by examination of alopecia-protocol horizontal histologic sections. A 72-year-old female presented to her dermatologist with a chief complaint of hair loss and pruritus.

Bone Matrix-forming Tumors.

Bone matrix-forming tumors are a group of neoplasms that exhibit differentiation toward any stage of osteoblast development. Their clinicopathologic features can resemble one another, yet their clinical management may vary significantly. Therefore, appropriate treatment requires accurate diagnosis, which can be challenging, especially with limited biopsy specimens.

Giant Cell-Rich Tumors of the Skeleton.

The accurate diagnosis of giant cell-rich tumors of bone is challenging, especially in limited tissue samples. This diverse group of neoplasms have similar and often ambiguous clinical presentations, radiologic features, and morphologic characteristics. During the last decade, the discovery of pathogenic recurrent genetic alterations has allowed the development of immunohistochemical surrogate markers and FISH assays that can help differentiate the entities of this broad group from one another.