Clinical, pathologic, and molecular analyses of superficial low-grade fibromyxoid sarcoma in two young patients: A rare and deceptive mimic of benignancy.

Low-grade fibromyxoid sarcoma (LGFMS) is a histopathologically deceptive soft tissue neoplasm with bland cytology, which is typically encountered in deep soft tissue of adults. We report two cases of superficial LGFMS in young patients (16 and 21 years old, respectively), which were difficult to diagnose on histopathologic and clinical findings alone. LGFMS commonly mimics benign neoplasms such as cellular neurothekeoma, fibromatosis, neurofibroma, and perineurioma. Malignancies included in the differential diagnosis are soft tissue neoplasms such as dermatofibrosarcoma protuberans and myxofibrosarcoma. A high degree of reported variation in pattern and cellularity among LGFMS further complicates the diagnosis. Careful examination and appropriate immunohistochemistry panels including MUC4 are essential for narrowing the differential diagnosis. Molecular studies for possible FUS translocation can confirm the diagnosis of LGFMS. Sufficient sampling and workup of these lesions are critical, especially in younger patients. Young age and superficial presentation can easily sway dermatopathologists/dermatologists toward an incorrect diagnosis of benignancy.

Angiokeratoma-like purpuric palmar nodules following chemotherapy.

We describe a patient with leukemia undergoing chemotherapy who developed painful purpuric nodules of the digits. These findings were concerning for endocarditis (clinically) and angiokeratomas on gross histology. After extensive evaluation, we report the development of painful purpuric nodules as a likely side effect of the patient's therapeutic regimen (hydroxyurea, danorubicin, cytarabine, and methotrexate).

Updates on the Pathology and Management of Nail Unit Tumors and Dermatoses.

Nail unit pathology is indispensable to reach an accurate diagnosis of nail tumors as well as inflammatory disorders. This review article provides an update from the most recently published studies on the pathology and management of nail unit tumors and inflammatory disorders. Recent findings of nail clipping histopathology are described first, followed by discussing recent data on the diagnosis and surgical management of several types of nail unit tumors, ending with discussing the recent discoveries in selected nail unit inflammatory disorders.

Indeterminate Cell Histiocytosis Mimicking Rosacea.

Indeterminate cell histiocytosis (ICH) is a rare proliferative disorder of histiocytes, which display morphologic and immunophenotypic characteristics of both Langerhans cell histiocytosis (LCH) and non-Langerhans cell histiocytosis (NLCH). We describe an unusual clinical presentation of ICH mimicking rosacea and provide a relevant review of the literature.

Shapiro xanthogranuloma: An essential diagnosis for dermatologists and dermatopathologists to recognize to avoid misdiagnosis of a hematopoietic malignancy in infants and neonates.

The Shapiro xanthogranuloma is a histopathologic form of xanthogranuloma that shows closely packed monomorphous cells, which can extend into the subcutaneous fat; it usually lacks routine diagnostic features of xanthogranuloma. Herein we describe two cases of Shapiro xanthogranuloma occurring in a neonate and in an infant, which were initially thought to be hematologic malignancies. One patient's presentation as a "blueberry muffin baby" added to the diagnostic confusion. Pediatric dermatologists, dermatologists, and dermatopathologists need to be aware of the Shapiro xanthogranuloma and its clinicopathologic features to avoid misdiagnosis of a hematopoietic malignancy in neonates and infants.

Nail Unit Schwannoma: An Important Consideration in the Differential Diagnosis of Soft Tissue Tumors Affecting the Nail Apparatus.

Schwannoma is a tumor of schwann cell proliferation which presents as a solitary, soft, skin-colored dermal or subcutaneous papulo-nodule most commonly on the flexor part of extremities and head and neck areas. Here, we report a case of nail unit schwannoma, which is a rare tumor of the nail apparatus with only 4 other prior reports in the literature. This case illustrates the importance of including subungual schwannoma in the clinical differential diagnosis of subungual soft tissue tumors. We include a literature review which catalogs and summarizes the current knowledge regarding this unusual nail unit neoplasm.