Sweet Syndrome as a Herpetiform Mimic: A Diagnostic Challenge.

ABSTRACT: The authors present a singular case of Sweet syndrome (acute febrile neutrophilic dermatosis) manifesting with an unusual herpetiform clinical presentation, underscoring the imperative for its inclusion in differential diagnoses of herpetic infections. A 26-year-old female patient with a systemic lupus erythematosus history presented with facial edema, hyperthermia, cephalalgia, and polyarticular pain. Dermatological examination revealed clustered, vesicle-like papules on erythematous, edematous skin, mimicking herpetic infection. Elevated acute-phase reactants and urine anomalies were noted. Histopathology confirmed Sweet syndrome, characterized by superficial and deep neutrophilic dermatitis, karyorrhexis, and papillary dermal edema. The patient responded to corticosteroid therapy and a brief antibiotic course, resolving both systemic and cutaneous symptoms. This case is remarkable for its atypical herpetiform presentation, a clinical rarity in Sweet syndrome, challenging the conventional diagnostic process. It emphasizes the necessity of considering Sweet syndrome in differential diagnoses when encountering herpetiform lesions, particularly in patients with autoimmune backgrounds. This case contributes significantly to the understanding of Sweet syndrome's clinical variability and highlights the critical role of thorough clinicopathological evaluation in achieving accurate diagnosis in complex dermatological disorders.

Pseudolymphomatous Cutaneous Angiosarcoma Presenting With Persistent Firm Facial Edema in a Patient With Systemic Sclerosis.

ABSTRACT: Pseudolymphomatous cutaneous angiosarcoma (cAS) is a rare subtype characterized by a prominent lymphocytic infiltrate, posing diagnostic challenges due to its resemblance to lymphoid neoplastic processes. We present a novel case highlighting the clinical and histopathological features, notably its association with persistent firm facial edema in a patient with systemic sclerosis (SSc). A 47-year-old woman with a 21-year history of SSc presented with firm palpebral edema evolving to involve the entire face and cervical region over six months. Diagnostic imaging revealed inflammatory changes in orbital regions, supradiaphragmatic lymphadenopathies, and lytic lesions. Skin biopsy demonstrated a diffuse neoplasm with vascular channels and solid areas, accompanied by dense lymphocytic proliferation. Pseudolymphomatous cutaneous angiosarcoma, a rare malignant neoplasm, exhibits variable clinical presentations and rapid progression. Histologically, it manifests as irregularly shaped vascular channels lined by prominent endothelial cells. Immunohistochemistry, particularly markers such as v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG), aids in diagnosis. Notably, this case marks the first presentation of cAS with persistent facial edema in SSc, highlighting the association between SSc and cancer risk. This case underscores the diagnostic challenges posed by cAS and emphasizes the importance of early detection for optimal patient outcomes. Further understanding of its association with autoimmune disorders such as SSc is crucial for comprehensive management strategies.

Granulomatous Panniculitis as an Initial Manifestation of Sjögren Syndrome.

ABSTRACT: A 65-year-old woman presented with unexplained weight loss, recurrent fever, and a dermatosis with painful nodules on the extremities. Biopsies showed focal lobular panniculitis with neutrophilic microgranulomas. Comprehensive investigations ruled out infection and hematologic and solid organ neoplasms. Laboratory results showed anti-Ro/SSA and anti-La/SSB antibody positivity, and elevated inflammatory markers. Dry mouth and eye were confirmed. The diagnosis of Sjögren syndrome with cutaneous panniculitis was established. Prednisone treatment with 30 mg/d resulted in remission of fever and pain improvement. This case emphasizes Sjögren syndrome as an autoimmune disease with multiple cutaneous manifestations and highlights its association with granulomatous panniculitis.

Clinical, molecular, and histological characteristics of severely necrotic and fatal mpox in HIV-infected patients.

BACKGROUND: This case series of 5 patients with severely necrotic mpox highlights the predominantly necrotic nature of lesions seen in cases of severe mpox as shown by skin and lung biopsy, as well as the extensive dissemination of the infection, as shown by polymerase chain reaction (PCR) assessment in different body sites. CASE PRESENTATIONS: Patients were male, the median age was 37, all lived with HIV (2 previously undiagnosed), the median CD4+ cell count was 106 cells/mm3, and 2/5 were not receiving antiretroviral treatment. The most common complication was soft tissue infection. Skin and lung biopsies showed extensive areas of necrosis. Mpox PCR was positive in various sites, including skin, urine, serum, and cerebrospinal fluid. The initiation of antiretroviral treatment, worsened the disease, like that seen in immune reconstitution syndrome. Three patients died due to multiple organ failure, presumably associated with mpox since coinfections and opportunistic pathogens were ruled out. CONCLUSIONS: Severely necrotic manifestations of mpox in people living with advanced and untreated HIV are related to adverse outcomes.

Histopathological and Immunohistochemical Characterization of Skin Biopsies From 41 SARS-CoV-2 (+) Patients: Experience in a Mexican Concentration Institute: A Case Series and Literature Review.

ABSTRACT: The SARS-CoV-2 pandemic brought countless clinical and pathophysiological questions. Although mucocutaneous infections are the most visible, they are among the least studied. This article provides relevant information to characterize morphologically and immunohistochemically the dermatoses from patients with COVID-19, during the first year of the pandemic. Immunohistochemistry reactions against the spike protein were performed in 48 skin biopsies, and the positive cases were classified according to their histomorphology; at the end, 41 biopsies led us to identify 12 morphological patterns that mimic other skin pathologies, among which pityriasiform patterns predominate. For the literature review, we selected cases of SARS-CoV-2 dermatoses that included complete histopathological information and that were published during the same interval of time; after careful evaluation, 205 biopsies were selected and then classified into 8 groups according to previously published proposals. Dermatoses associated with SARS-CoV-2 are as diverse in their clinical expression as in their histopathology, mimicking entities totally unrelated to COVID-19. Furthermore, some of these groups are characteristically associated with an aggressive course of the disease. Undoubtedly, it is necessary to delve into the possibility that these findings are translatable into prognostic and therapeutic factors.

Porocarcinoma with areas of mucinous differentiation suggesting multilineage differentiation.

Porocarcinoma is an infrequent malignant adnexal carcinoma, with some histopathological variants described, such as the clear cell, the sarcomatoid or the pigmented porocarcinoma. We report an invasive porocarcinoma showing areas of tumor cells floating in prominent dermal mucin, simulating mucinous carcinoma, that we consider a new histopathological variant of porocarcinoma. We report a 74-year-old male with previous history of multiple basal cell carcinomas that presented a nodule on his left temple. Histopathologic study showed a large ulcerated multilobular tumor composed of thickened cords of cells emanating from a hyperplastic epidermis and showing a mixed infiltrative and pushing pattern in the dermis. Poroid differentiation was observed in most of the neoplasm, both in intraepidermal and dermal invasive component. Within the neoplasm a prominent area where these small nests with clear formation of ducts were floating in mucinous pools with few septa intermingled was observed, simulating a primary cutaneous mucinous carcinoma. Cytology, immunohistochemistry and the presence of both neoplastic areas as closely related and with multiple points of connectivity favors the consideration of a composite tumor in this peculiar case. Other differentials are discussed.

Histopathology of aging of the hair follicle.

Hair follicles experience several changes with aging, the most noticeable of which is graying of the hair shaft due to loss of melanin. Additional changes in the diameter and length of the hair have contributed to the concept of senescent alopecia, which is different from androgenetic alopecia according to most. Graying happens in most individuals, although in different grades and starting at different ages. It is related to a decrease in the number and activity of the melanocytes of the hair bulb, which eventually completely disappear from the bulb of the white hair. Residual non-active melanocytes remain in the outer root sheath and in the bulge, which allows for repigmentation of the hair under certain stimuli or conditions.

Intramural schwannoma involving a vein.

Schwannoma involving the blood vessels is a rare phenomenon. So far, only three cases of intravascular schwannoma have been described (all of which were intraluminal), and the origin of the schwannoma in such cases is not yet completely understood. Here, we describe a very rare intramural venous schwannoma in the subcutaneous right prepatellar area of a 31-year-old man. The schwannoma grew by enlarging and thickening the blood vessel wall, between two preserved layers of the vein. In some areas, there was erosion of the luminal layer, with fibrin apposed to the tumor. The tumor expressed S100 and was negative for CD31, CD34, desmin, and smooth muscle actin. The expression of p16 was preserved. Endothelial markers such as CD31 and Factor VIII showed the endothelial lining (which was D2-40-negative) above the tumor. Although degenerative atypia was present, there were no mitotic figures or necrosis identified.

Histopathology of Cutaneous Aging.

Aging is (so far) an inexorable and irreversible path in all species and organisms. In human beings, aging involving the skin has a special meaning because our appearance has become crucial for our social life in the modern world. Knowledge of the morphologic changes that happen during the aging process is crucial for understanding its pathogenesis, which in turn is necessary to approach it and even revert it. Skin aging happens because of 2 main sets of changes. Many -although not all-are the cause of exposure to external agents (extrinsic aging), of which the most important is solar exposure (also known as photoaging). In addition, skin also degenerates by mechanisms linked to genetically programed information (intrinsic aging). In this article, the histopathologic changes evident in exposed and nonexposed skin are examined.

Nutritional Deficiency-Related Oral and Cutaneous Lesions in an Obese Patient.

The cutaneous and oral lesions related to nutritional deficiencies are scarcely reported. Micronutrient deficiencies may significantly affect mouth mucosa and skin, causing great morbidity. We report an extraordinary case with detailed clinical and microscopic findings affecting the oral cavity and skin. Physicians must be familiar with these manifestations to suspect the diagnosis.

Polypoid Spitz Nevus With a Halo Reaction.

Approximately, 2% of Spitz nevi are polypoid; between 3.6% and 7.4% present with a halo reaction. In tandem, these low percentages make the presence of a polypoid Spitz nevus with a halo reaction uncommon; we have not found reports of any previous cases. In the current report, we present a polypoid Spitz nevus with a halo reaction on the back of a 10-year-old male and discuss the morphologic findings. The lesion showed preserved nuclear expression of BAP1. There was no immunohistochemical expression of BRAF and ALK, while the melanocytic cells expressed p16. Comparative genomic hybridization was performed, and no significant aberrations were found. Only 2 small losses were evidenced in chromosome 8. The patient has been followed now for 2 years with no recurrence.

Mucin as a diagnostic clue in dermatopathology.

Mucins are high-molecular weight glycoproteins typically found in normal skin in small amounts. There are several reports regarding different types of cutaneous mucinosis. In this report, we discuss mucins in dermatopathology as a diagnostic clue of some well-known entities and some less frequent cutaneous diseases. We also emphasize mucin as a sign in the differential diagnosis between conditions that show histopathological overlap. Lastly, we discuss the locations and circumstances in which mucin could be considered almost normal or physiological.

Pemphigus foliaceus with circinated plaques and neutrophil pustules.

Pemphigus is a group of autoimmune intraepidermal bullous diseases; being pemphigus foliaceus (PF) and pemphigus vulgaris (PV) the most common subtypes. Pustular variants are scarcely reported for both PV and PF. The purpose of this manuscript was to describe the clinical, microscopic and immunologic findings of an atypical case of PF presenting with pustules, including a review of the literature. PF is described as blisters and because this entity is rare, it is not known for the general medical community that they are other clinical features that can be seen as this one we present here with pustules.

Spitz Nevus Intermingling With a Hemangioma.

We report on a Spitz nevus intermingling with a hemangioma in the same biopsy from the right thigh of a 10-year-old boy. The hemangioma was made of dilated vessels in superficial areas but of narrow and angulated vessels in the deep and lateral zones. The Spitz nevus was typical, showing maturation, and no worrisome cytological features. The immunohistochemical study demonstrated expression by the vascular component of CD31, CD34, factor VIII-related antigen, and Wilms tumor 1, whereas the vessels did not express D2-40 human herpes virus 8 or glucose transporter-1. The melanocytic component expressed HMB-45 (weakly and mainly in the superficial zones), Melan-A and S-100 protein. A perivascular continuous layer of pericytes expressing smooth muscle actin was also evident.

Focal Epithelial Hyperplasia in Adult Patients With HIV Infection: Clearance With Topical Imiquimod.

Case 1 A 41-year-old man with human immunodeficiency virus (HIV) 1 diagnosed 16 years prior to his consultation was referred for an 8-month history of multiple painless lumps in his mouth. He had A2 status (CD4 cell count of 273 cells/mm3 and viral load of 43,000 copies/L) and was taking treatment with lamivudine/zidovudine (combivir) and efavirenz. Physical examination showed multiple small mucosal-colored and lobulated papulonodules located in the palate and lower gingiva and a whitish verrucous plaque on the lower labial mucosa (Figure 1a). The lesions were diagnosed clinically as focal epithelial hyperplasia (FEH) and further confirmed by classical histopathological findings (Figure 1b). He had previously received unspecified treatment; thus, topical 5% imiquimod cream was initiated every night. Mild erosion and ulceration developed in the upper labial mucosa, which were managed with lubrication (petrolatum ointment). After 2 weeks, all of the small lesions disappeared and the largest plaque resolved 1 week later (Figure 1c). A small residual mass in the area of biopsy, suggesting a scar, remained on the lower lip. The area was removed surgically and corresponded to fibrosis histologically, with no evidence of human papillomavirus (HPV) infection. CD4 cell count (694 cells/mm3) and viral load (<40 copies/L) did not show remarkable changes after imiquimod administration. No serious side effects were observed and the patient has remained free of disease after 1 year of follow-up.

Three cases of bullous morphea: histopathologic findings with implications regarding pathogenesis.

Bullous morphea is a rare variant and is not frequently reported. We present three cases of bullous morphea. Although lymphangiectases have been suggested as the most likely mechanism for the development of the bullae in cases of morphea, none of the cases presented with lymphangiectases. To the contrary, all of our cases showed hemorrhagic content in the bullae, which suggests local trauma as a mechanism involved in bulla formation.

Combined cutaneous smooth muscle hamartoma and nevus flammeus.

We report on a combined cutaneous smooth muscle hamartoma and reticulate port-wine stain on the thigh of a 26-year-old woman. The lesion measured 30 cm in longest diameter and presented clinically with a macular erythematous telangiectatic vascular appearance. It was focally ulcerated, which represented the patient's main complaint. Histopathological study demonstrated smooth muscle bundles closely intermingled with a vascular component comprised of capillaries and venules. Such a morphological presentation is, to the best of our knowledge, unique in the literature.

Pulse granuloma of the lip: morphologic clues in its differential diagnosis.

Pulse granuloma is not a common condition in cutaneous pathology. In diagnosing this condition, it is essential to determine if the foreign fragmented bodies are really vegetable parts. Certain vegetable structures, such as hyaline rings, have been clearly emphasized in the literature. However, other vegetable parts can show certain morphologic similarities with animal structures, especially if observed in a fragmented biopsy, as is the case with the pericarp (which can mimic the cuticle of a maggot) or the endosperm (which can mimic the fat cells of the larva). Herein, we present a case of pulse granuloma involving the lip, an uncommon location for this condition. We also describe the histopathologic appearance of experimentally obtained maggots and pupae, as well as that of several vegetable seeds. We compare some of the vegetable and animal structures and emphasize the differential diagnosis between them.

Papular mucinosis of the breast after radiation therapy.

Localized papular mucinosis is a type of mucinosis induced by several different causes. However, to the best of our knowledge, prior radiation therapy has not been reported to be related to papular mucinosis. We present a case of a 47-year-old woman who had undergone an operation for a breast carcinoma 2 years earlier and received local radiotherapy in the affected breast. Currently, she presents multiple erythematous papules that are caused by abundant dermal mucin deposits. We discuss some potential differential diagnoses.

Systemic amyloidosis presenting with glans penis involvement.

Penile amyloidosis has been reported on many occasions in the literature, but all of these have been forms of primary cutaneous amyloidosis. Systemic amyloidosis presenting with a penile ulcer as the first manifestation has not previously been reported. We present two patients in whom an ulcer of the glans penis was the first complaint that led to a diagnosis of systemic amyloidosis. In both patients, lambda light chain type amyloid was showed immunohistochemically. Both patients presented with other manifestations of systemic amyloidosis, including nail dystrophy characterized by onycholisis, trachyonychia and onychoschizia.