We report a 70-year-old man with a long-standing history of eruptive syringomas, including scattered plaque-type syringomas that raised clinical concern for basal cell carcinoma. A biopsy of a plaque-type lesion on the left clavicle revealed a syringoma with superficial follicular infundibular cysts resembling those of microcystic adnexal carcinoma (MAC). The lesion also exhibited cords and trabeculae streaming from the epidermis, and solid nests of variable sizes extending to the deep dermis, reminiscent of the solid variant of MAC. Excision revealed a fairly circumscribed tumor within a sclerotic stroma that did not invade nerve or infiltrate fat, supporting a diagnosis of plaque-type syringoma. Additional lesions have since been biopsied, revealing similar findings, but none of them have been re-excised nor have they recurred. The patient had facial milia, but was not thought to have Nicolau-Balus syndrome given the absence of atrophoderma vermiculata and a lack of a pertinent family history. Herein, we discuss the histomorphologic diversity of syringomas and helpful findings that distinguish them from carcinoma. An unequivocal distinction between syringoma and MAC is not always feasible on a partial sample, but awareness of rare syringoma variants can sometimes prevent unnecessary surgery.

Oral-facial-digital syndrome type 1 (OFD1) is an X-linked dominant development disorder due to mutations in the OFD1 gene. It is characterized by facial, oral, and digital malformations, although expression is variable. Skin manifestations are frequent (20%-30% of patients) and characterized by evanescent milia and patchy alopecia. Trichoscopic findings (broken hairs, black dots, pili torti) can resemble tinea capitis, although such findings have not been well characterized. High clinical suspicion of ectodermal dysplasia-like syndromes due to trichoscopy findings, absence of response to long-term antifungal therapy, and the presence of midline anomalies can raise suspicion for OFD1, which can be confirmed by genetic testing and enable diagnosis.

Differentiating neuromyelitis optica spectrum disorder (NMOSD) from its mimics is crucial to avoid misdiagnosis, especially in the absence of aquaporin-4-IgG. While multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein-IgG associated disease (MOGAD) represent major and well-defined differential diagnoses, non-demyelinating NMOSD mimics remain poorly characterized. We conducted a systematic review on PubMed/MEDLINE to identify reports of patients with non-demyelinating disorders that mimicked or were misdiagnosed as NMOSD. Three novel cases seen at the authors' institutions were also included. The characteristics of NMOSD mimics were analyzed and red flags associated with misdiagnosis identified. A total of 68 patients were included; 35 (52%) were female. Median age at symptoms onset was 44 (range, 1-78) years. Fifty-six (82%) patients did not fulfil the 2015 NMOSD diagnostic criteria. The clinical syndromes misinterpreted for NMOSD were myelopathy (41%), myelopathy + optic neuropathy (41%), optic neuropathy (6%), or other (12%). Alternative etiologies included genetic/metabolic disorders, neoplasms, infections, vascular disorders, spondylosis, and other immune-mediated disorders. Common red flags associated with misdiagnosis were lack of cerebrospinal fluid (CSF) pleocytosis (57%), lack of response to immunotherapy (55%), progressive disease course (54%), and lack of magnetic resonance imaging gadolinium enhancement (31%). Aquaporin-4-IgG positivity was detected in five patients by enzyme-linked immunosorbent assay (n = 2), cell-based assay (n = 2: serum, 1; CSF, 1), and non-specified assay (n = 1). The spectrum of NMOSD mimics is broad. Misdiagnosis frequently results from incorrect application of diagnostic criteria, in patients with multiple identifiable red flags. False aquaporin-4-IgG positivity, generally from nonspecific testing assays, may rarely contribute to misdiagnosis.

Orofaciodigital syndrome (OFD) can have variable phenotype and presents with oral anomalies, facial dysmorphism, and digital malformations like syndactyly, and polydactyly. Other presentations also include renal and cardiac defects, and central nervous system anomalies like hydrocephalus and cerebellar abnormalities. OFD1 is a X-linked dominant form of the syndrome presenting in females with mutations in CXorf5 or OFD1 gene. We describe a young child with sparse hairs, milia over face and absence of corpus callosum. Next generation sequencing showed frameshift pathogenic variant in the exon 13 of the OFD1 gene, consistent with diagnosis of OFD1.

Idiopathic calcinosis cutis is an uncommon form of calcinosis cutis. It may present as tumoral calcinosis, subepidermal calcified nodules or scrotal calcinosis. Subepidermal calcified nodules may also present as milia-like lesions commonly seen in children with Down's syndrome in the absence of tissue damage or metabolic disorders, it has been seldom reported in adults. The treatment of choice is surgical excision. However, a surgical approach may not always be beneficial to the patient given the cosmetic outcomes. Here, we describe the successful use of a CO2 laser in the treatment of milia-like calcinosis cutis of the forehead in an adult without Down's syndrome. To describe the treatment of Milia-like idiopathic calcinosis cutis of the forehead in an adult without Down's syndrome successfully treated with a CO2 laser. We report a case of a 48-year-old man who presented with skin-colored hard asymptomatic papules on the forehead that started about 9 years ago, a biopsy was performed and a diagnosis of milialike calcinosis cutis was made. Surgical excision was discarded regarding the location and the number of lesions, instead, a CO2 laser was used to treat this condition. Successful laser excision of the lesions with appealing cosmetic results. CO2 laser seems to be a valuable tool to treat milia-like calcinosis cutis lesions.