Fluorescent Imaging as a Component of Diagnosing Pyoderma Gangrenosum: A Case Report.

ABSTRACT: A 64-year-old White woman was admitted to the hospital with complaint of progressive right hip ulceration at the wound site following a total right hip arthroplasty. Initial history and physical examination gave a leading differential diagnosis of pyoderma gangrenosum. Until recently, the exclusion of infection for pyoderma gangrenosum has been largely clinical and supported by cultures/biopsies demonstrating the absence of infection. The MolecuLight i:X (MolecuLight, Toronto, Ontario, Canada) is a novel bedside fluorescent imaging device capable of determining the bacterial burden within a wound in real time. Fluorescent imaging excluded infection at the initial visit, and debridement was avoided. Subsequently, pathergy was avoided as well. The patient was started on topical clobetasol with hypochlorous acid-soaked dressings. She also received 80 mg daily of prednisone and high-dose vitamin D3 (10,000 IU). Recovery was complicated by a deep tunnel along the incisional line at 3 months postdiagnosis, which required slowing of the prednisone taper and the addition of colchicine. Repeat cultures grew Parvimonas, Pseudomonas, and Streptococcus species. Appropriate antibiotics were given. The patient was transitioned from prednisone to adalimumab and started on negative-pressure wound therapy. Negative-pressure wound therapy was discontinued at 5 months, and the wound resolved at 6 months.

Hand-foot skin reaction with primarily dorsal involvement in a patient with metastatic renal cell carcinoma on cabozantinib.

A 61-year-old man with metastatic renal cell carcinoma on cabozantinib developed hand-foot skin reaction with predominantly dorsal involvement including painful violaceous plaques over the joints and keratotic yellow plaques on the palmar fingers. The medication was discontinued with resolution of the plaques and later reinitiated at a lower dose uneventfully.

An Intrapatient Concordance Study of Mismatch Repair Protein Immunohistochemical Staining Patterns in Patients With Muir-Torre Syndrome.

Importance: Appropriate use criteria for Muir-Torre syndrome (MTS) screening suggest that mismatch repair protein (MMRP) immunohistochemical (IHC) testing is usually appropriate in patients with 2 or more sebaceous neoplasms (SNs). While MTS is known to be caused by a germline mutation in mismatch repair genes, data are limited as to whether individual sebaceous tumors in these patients with multiple lesions show identical MMRP IHC staining patterns. Objective: To determine concordance of MMRP IHC staining patterns in lesions of patients with MTS who have multiple SNs. Design, Setting, and Participants: This retrospective single-center case series evaluated 38 SNs in 11 patients with MTS confirmed by genetic testing for MMRP IHC staining patterns. Tumor sites were classified as either facial or extrafacial. Data were collected between January 1, 2007, and January 1, 2018. Main Outcomes and Measures: In each patient, MMRP IHC staining patterns for SNs were compared with one another to evaluate intrapatient concordance between lesions, and to the patient's known germline mutation. Results: A total of 11 patients (7 women and 4 men) with MTS, with a mean (SD) age of 59.3 (10.6) years at time of SN biopsy, were identified. There was high concordance between MMRP IHC staining results (2-4 lesions per patient) and the patient's mutation status, with 36 of 38 total lesions (95%) matching (sensitivity, 94.7%; 95% CI, 82.3%-99.4%). Extrafacial site tumors represented 16 of 38 total lesions (42%) and demonstrated 100% concordance of IHC results to germline mutation. Only 1 of 11 patients (9%) demonstrated discordant results, with both lesions in this patient occurring on a facial site. Conclusions and Relevance: In patients with known MTS, SNs present with highly concordant MMRP IHC staining profiles across multiple lesions. There is also a strong association with underlying germline mutations. A diagnosis of MTS might be supported by MMRP IHC when the pretest probability is high.

Nail Unit Glomus Tumor with Myxoid and Symplastic Change Presenting with Longitudinal Erythronychia.

Glomus tumors are soft tissue neoplasms, which are most frequently encountered in the nail unit and generally straightforward to diagnose by histopathology. The typical clinical presentation is that of a circular violaceous or erythematous lesion within the nail bed. However, there are rare variants of glomus tumors which may pose diagnostic challenges because of the presence of unusual histologic features. Herein we report such a glomus tumor that demonstrates the rare combination of both myxoid and symplastic change. The clinical presentation of longitudinal erythronychia, as seen with this case, can occur with glomus tumors, but it is unusual, as longitudinal erythronychia on a single nail usually is caused by an onychopapilloma. The distinct nuclear atypia characteristic of symplastic change can raise alarm for a malignant process but the clinical course is benign. It is essential for dermatopathologists to be aware of this unusual variant of a glomus tumor in order to avoid overdiagnosis of atypia, which could result in unnecessary aggressive surgery. While unusual, there is good clinicopathologic correlation of the glomus tumor presenting with longitudinal erythronychia.