Background: Non-neural granular cell tumor (NNGCT) is an uncommon neoplasm of controversial histogenesis and its histopathologic differential diagnosis includes, in addition to conventional GCT, other dermal tumors that may exhibit granular cell change. Methods: Three patients with a diagnosis of NNGCT were identified in the authors' files. Hematoxylin and eosin-stained sections and immunohistochemical studies were performed. Results: Histopathological study of the three lesions showed dermal proliferation of granular cells arranged in thick fascicles between collagen bundles. The lesions showed positivity for Factor XIIIa, CD163, CD68, NKIC3, vimentin, ALK, fascin, and cyclin D1. Conclusion: To our knowledge, positivity for cyclin D1 has not been reported to date in NNGCT. In borderline cases, where the diagnosis is unclear despite histopathologic and immunohistochemical findings, positivity for cyclin D1 may favor the diagnosis of NNGCT. Further investigations to assess the differentiation of this rare neoplasm are needed.

Pagetoid reticulosis (PR) is a rare lymphoproliferative disorder with indolent behavior considered a variant of mycosis fungoides. It is characterized by marked epidermotropism of the neoplastic lymphocytes. Since its original description, five cases have been reported in children. We report a new case of PR with an immunohistochemical profile not previously described in children. K E Y W O R D S epidermotropic lymphoproliferative disorder, immunophenotype, mycosis fungoides, pagetoid reticulosis

Microcystic adnexal carcinoma (MAC) is a low-grade adnexal carcinoma with controversial lines of differentiation. We present here an example of MAC showing histopathologic findings of germinative follicular differentiation in the form of solid aggregates of trichoblastoma intermingled with neoplastic aggregates of MAC. Immunohistochemical findings, showing positivity for PHLDA1 and negativity for BerEp4 in neoplastic aggregates of trichoblastoma, also supported a germinative follicular differentiation. Follicular differentiation in MAC supports an apocrine line of differentiation for this neoplasm.

Targeted anticancer therapy is being used with greater frequency and dermatologic toxicities are among the most frequent adverse events of these drugs. However, histopathological features of these adverse events are not yet well characterized. We present two cases of clinically different cutaneous toxicities on two patients with hematologic neoplasia. They were treated with different drugs and in both cases medications shared inhibition of PI3K as mechanism of action. The skin biopsy specimen showed endothelial cell atypia with large nuclei and mitotic figures. To the best of our knowledge, no other cases with these striking histopathologic findings have been reported with PI3K inhibitors or other anticancer targeted therapy.

Toker cells (TCs) are sometimes present in the nipple epidermis as oval cells with pale cytoplasm and roundish nuclei. In most cases, TCs may be easily distinguished from cancerous cells of Paget disease of the nipple (PCs). Especially in TC hyperplasia, in which mild-to-moderate atypia may be present, it may be challenging to distinguish between TCs and PCs. The combination of chronic inflammatory changes in the nipple, in the context of Zuska disease, and TC hyperplasia, may easily lead to an erroneous diagnosis of mammary Paget disease.

Pigmented epidermotropic breast cancer metastases are a rarity, often clinically misdiagnosed as melanocytic lesions. Histopathologically, they show a dermal proliferation of neoplastic metastatic cells that extend to the overlying epidermis in a pattern identical to that seen in primary Paget disease (PD). Differential diagnosis should be established with entities with a similar presentation, such as pigmented mammary PD and malignant melanoma. Immunohistochemistry may be useful for this purpose. We present a new case of pigmented epidermotropic breast cancer metastases with a particularly unusual feature: the absence of dermal infiltration by neoplastic cells, thus considered as pure epidermotropic metastatic involvement.

personal protective equipment (PPE); however, hospital supplies were subsequently assured and local policies changed. Fortunately, we were able to avoid reliance on teledermatology and its associated limitations that may miss important diagnoses. 6 Acute dermatitis featured more in 2020, similar to findings from other countries, 5 and as expected subacute referrals reduced (e.g. NMSC). Interestingly, there was a rise in scabies presentations, which was experienced by other local private practices. This is contrary to the expectation that lockdown and social distancing would reduce opportunities for intimate or close contact. Similar observations have been made regarding sexually transmitted diseases, wherein delayed diagnosis can have more serious implications. 4,5,7 It is thus important to encourage testing for STIs despite COVID-19. Unlike our international counterparts, we did not experience a sustained significant reduction in consults and have not needed to dramatically change our practice. However, the long-term consequences of potentially delayed diagnosis of subacute conditions in Australian dermatology practice need to be further evaluated, including trends in private and primary care practices. Our experience also shows that demand for hospital dermatology services continues and departments should learn from the experiences of international counterparts for better preparedness for future pandemics. ETHICALEthical committee review was not sought as guided by the 2014 NHMRC Guidelines for Quality Assurance and Evaluation Activities, and this was a clinical audit. FINANCIAL SUPPORTNo funding was acquired or utilised for this report.

Gene profiling using a customized NanoString platform can be applied to routine MF samples, revealing their specific molecular features. This study shows that MF samples carry a signature derived from individual molecular features found in consecutive biopsies.