Nail Amyloidoma: Two Case Reports of a New Entity.

Introduction: Amyloidosis is a group of diseases characterized by extracellular deposits of abnormal insoluble proteins in different tissues. Amyloidoma is a localized tumoral deposit of amyloid in the absence of systemic amyloidosis, and it has been described in different anatomic sites. We report two cases of amyloidoma in the nail unit and provide insights into this recently described entity. Case Presentation: Both cases presented as an asymptomatic, slowly growing nodule underneath the distal nail bed of a toe with associated onycholysis. Histopathology was characterized in both patients by the presence of deposits of Congo red-positive, homogeneous, amorphous, and eosinophilic material within the dermis and subcutaneous tissue admixed with aggregates of plasma cells. In both cases, an extensive workup excluded systemic amyloidosis. Treatment was based on local excision, and no local recurrence or progression to systemic amyloidosis was observed at 1 year of follow-up. Conclusion: These are the first reports of amyloidomas of the nail unit. The clinical and histopathological presentations parallel those of an amyloidoma affecting the skin. Local excision seems to be an efficient treatment modality, but long-term follow-up is warranted in order to exclude recurrence, an associated marginal B-cell lymphoma, or progression to systemic amyloid L amyloidosis.

A clinicopathological description of COVID-19-induced chilblains (COVID-toes) correlated with a published literature review.

BACKGROUND: The abundance of publications of COVID-19-induced chilblains has resulted in a confusing situation. METHODS: This is a prospective single-institution study from 15 March to 13 May 2020. Thirty-two patients received PCR nasopharyngeal swabs. Of these, 28 patients had a thoracic CT-scan, 31 patients had blood and urine examinations, 24 patients had skin biopsies including immunohistochemical and direct immunofluorescence studies, and four patients had electron microscopy. RESULTS: COVID-19-induced chilblains are clinically and histopathologically identical to chilblains from other causes. Although intravascular thrombi are sometimes observed, no patient had a systemic coagulopathy or severe clinical course. The exhaustive clinical, radiological, and laboratory work-up in this study ruled-out other primary and secondary causes. Electron microscopy revealed rare, probable viral particles whose core and spikes measured from 120 to 133 nm within endothelium and eccrine glands in two cases. CONCLUSION: This study provides further clinicopathologic evidence of COVID-19-related chilblains. Negative PCR and antibody tests do not rule-out infection. Chilblains represent a good prognosis, occurring later in the disease course. No systemic coagulopathy was identified in any patient. Patients presenting with acral lesions should be isolated, and chilblains should be distinguished from thrombotic lesions (livedo racemosa, retiform purpura, or ischemic acral necrosis).

Histologic Patterns and Clues to Autoinflammatory Diseases in Children: What a Cutaneous Biopsy Can Tell Us.

Autoinflammation is defined by aberrant, antigen-independent activation of the innate immune signaling pathways. This leads to increased, pro-inflammatory cytokine expression and subsequent inflammation. In contrast, autoimmune and allergic diseases are antigen-directed immune responses from activation of the adaptive immune system. The innate and adaptive immune signaling pathways are closely interconnected. The group of 'complex multigenic diseases' are a result of mutual dysregulation of both the autoinflammatory and autoimmune physiologic components. In contrast, monogenic autoinflammatory syndromes (MAIS) result from single mutations and are exclusively autoinflammatory in their pathogenesis. Studying the clinical and histopathological findings for the various MAIS explains the phenotypical correlates of their specific mutations. This review aims to group the histopathologic clues for autoinflammation into three recognizable patterns. The presence of these histologic patterns in a pediatric patient with recurrent fevers and systemic inflammation should raise suspicion of an autoinflammatory component in MAIS, or, more frequently, in a complex multigenic disease. The three major histopathological patterns seen in autoinflammation are as follows: (i) the 'neutrophilic' pattern, seen in urticarial neutrophilic dermatosis, pustular psoriasis, aseptic neutrophilic folliculitis, and Sweet's syndrome; (ii) the 'vasculitic' pattern seen in small vessel-vasculitis (including hypersensitivity/leukocytoclastic vasculitis, thrombosing microangiopathy and lymphocytic vasculitis), and intermediate-sized vessel vasculitis, mimicking polyarteritis nodosa; and (iii) the 'granulomatous' pattern. Beyond these three patterns, there are additional histopathologic clues, which are detailed below. It is important for a dermatopathologist to recognize the patterns of autoinflammation, so that a diagnosis of MAIS or complex multigenic diseases may be obtained. Finally, careful histopathologic analyses could contribute to a better understanding of the various clinical manifestations of autoinflammation.

Clinicopathologic and immunophenotypic characterization of lichen planopilaris and central centrifugal cicatricial alopecia: A comparative study of 51 cases.

BACKGROUND: The purpose of the study was to compare the histopathologic and immunophenotypic features of central centrifugal cicatricial alopecia (CCCA) and lichen planopilaris (LPP) to better characterize and differentiate these two clinical entities. CCCA remains an ill-defined and still-unsettled histologic entity and many hair loss experts regard CCCA to be histologically indistinguishable from LPP. Given the overlapping histologic features of these two lymphocyte-predominant cicatricial alopecias, and the lack of consensus regarding the significance of proposed distinctions, dermatopathologists face difficulty in providing clinicians and patients certainty with a definitive diagnosis of CCCA vs LPP. METHODS: We performed a retrospective review of 51 scalp biopsies of patients with either the clinical diagnosis of CCCA (27 cases) or LPP (24 cases). Clinical information, histologic features of hematoxylin-eosin-stained sections, and a panel of immunohistochemical markers were evaluated on scalp biopsies. Tested parameters were quantified, and statistical analysis was performed. RESULTS: Our study found no differences on either histologic assessment or immunophenotypic characterization between cases of classic LPP and CCCA. CONCLUSION: The conclusion of this study is that the inflammatory infiltrates in CCCA and LPP are not only histologically similar but also immunophenotypically indistinguishable.

Bullous Lupus Under Nivolumab Treatment for Lung Cancer: A Case Report With Systematic Literature Review.

BACKGROUND: Various immune-related adverse events (irAEs) have been reported to be associated with the use of immune checkpoint inhibitors. We report a case of a patient with lung cancer treated with nivolumab who developed a bullous eruption and give a systematic review of the literature on irAEs in patients treated with immune checkpoint inhibitors for lung cancer. CASE REPORT: A patient with lung adenocarcinoma developed a non-specific skin lesion at the time of his cancer diagnosis followed by flare episodes until the eighth cycle of nivolumab, when he developed a bullous lupus. As the first eruption had started a few months after his cancer diagnosis and was exacerbated during immunotherapy, a paraneoplastic origin is discussed. Since the patient also presented with flares under nivolumab, we reviewed reported irAEs. No bullous lupus was found but to date, 33 cases of paraneoplastic lupus and two of lupus erythematosus have been reported. CONCLUSION: To our knowledge, this is the first description of a bullous lupus exacerbated by nivolumab.

Shwachman-Diamond syndrome presenting with early ichthyosis, associated dermal and epidermal intracellular lipid droplets, hypoglycemia, and later distinctive clinical SDS phenotype.

Shwachman-Diamond syndrome (SDS) is a recessive ribosomopathy, characterized by bone marrow failure and exocrine pancreatic insufficiency (ePI) often associated with neurodevelopmental and skeletal abnormalities. The aim of this report is to describe a SDS patient with early ichthyosis associated with dermal and epidermal intracellular lipid droplets (iLDs), hypoglycemia and later a distinctive clinical SDS phenotype. At 3 months of age, she had ichthyosis, growth retardation, and failure to thrive. She had not cytopenia. Ultrasonography (US) showed pancreatic diffuse high echogenicity. Subsequently fasting hypoketotic hypoglycemia occurred without permanent hepatomegaly or hyperlipidemia. Continuous gavage feeding was followed by clinical improvement including ichthyosis and hypoglycemia. After 14 months of age, she developed persistent neutropenia and ePI consistent with SDS. The ichthyotic skin biopsy, performed at 5 months of age, disclosed iLDs in all epidermal layers, in melanocytes, eccrine sweat glands, Schwann cells and dermal fibroblasts. These iLDs were reminiscent of those described in Dorfman-Chanarin syndrome (DCS) or Wolman's disease. Both LIPA and CGI-58 analysis did not revealed pathogenic mutation. By sequencing SBDS, a compound heterozygous for a previously reported gene mutation (c.258 + 2T>C) and a novel mutation (c.284T>G) were found. Defective SBDS may hypothetically interfere as in DCS, with neutral lipid metabolism and play a role in the SDS phenotype such as ichthyosis with dermal and epidermal iLDs and hypoglycemia. This interference with neutral lipid metabolism must most likely occur in the cytoplasm compartment as in DCS and not in the lysosomal compartment as in Wolman's disease. © 2016 Wiley Periodicals, Inc.

Distinguishing diffuse alopecia areata (AA) from pattern hair loss (PHL) using CD3(+) T cells.

BACKGROUND: Distinguishing between diffuse subacute alopecia areata (AA), in which the peribulbar infiltrate is absent, and pattern hair loss is challenging, particularly in cases that lack marked follicular miniaturization and a marked catagen/telogen shift. OBJECTIVE: We sought to distinguish diffuse AA from pattern hair loss using CD3(+) T lymphocytes. METHODS: A total of 28 cases of subacute AA and 31 cases of pattern hair loss were selected and a 4-mm punch biopsy was performed. All the specimens were processed using the "HoVert" (horizontal and vertical) technique. In all cases, hematoxylin-eosin and immunohistochemical stains for CD3, CD4, CD8, and CD20 were performed. RESULTS: The presence of CD3(+) lymphocytes within empty follicular fibrous tracts (stela), even without a concomitant peribulbar infiltrate, is a reliable histopathological clue in supporting a diagnosis of AA (sensitivity 0.964, specificity 1, P ≤ .001). LIMITATIONS: Limited tissue for analysis remained in the clinical sample tissue blocks. CONCLUSION: The presence of CD3(+) T-cells within empty follicular fibrous tracts (stela) supports a diagnosis of AA.

Pseudoangiomatous xanthelasmoid mastocytosis: two case reports showing the hypervascularity of this rare variant of cutaneous mastocytosis.

Xanthelasmoid mastocytosis or xanthelasmoidea is a rare clinical variant of cutaneous mastocytosis characterized by a yellow hue of the clinical lesions, which are often misdiagnosed as juvenile xanthogranuloma. We present two pediatric cases of xanthelasmoid mastocytosis presenting as isolated mastocytomas, which are notable histopathologically for their hypervascularity. This pseudoangiomatous variant of cutaneous mastocytosis is important for pathologists to have knowledge of, so that a diagnosis of a vascular tumor is not rendered accidentally. The yellow hue has previously been explained by the usual deep and solid dermal mast cell infiltrate. In the two presented cases, however, the mast cell infiltrate was sparse, and the yellow color cannot be related to infiltrate density. We believe that the hypervascularity is at least one factor in the production of clinical xanthelasmoid appearance, and we propose the term 'pseudoangiomatous xanthelasmoid mastocytosis' to properly describe this rare variant of cutaneous mastocytosis.

Eruptive tumors of the follicular infundibulum presenting as hypopigmented macules on the buttocks of two Black African males.

We report two cases of eruptive tumors of the follicular infundibulum (TFI) with an unusual clinical presentation which has not been described previously in literature. In both cases, the appearance was strikingly similar, consisting of multiple asymptomatic hypopigmented macules on the buttocks of two Black African males, aged 38 and 55 years old. In both cases, the eruption had evolved over several months. The individual lesions were of similar size, approximately 1 cm, with irregular and ill-defined borders. Histopathological examination revealed a superficial and horizontal plate-like proliferation of keratinocytes emanating from the epidermis with multiple slender attachments. Pale keratinocytes were present within the epithelial plates. A Fontana stain showed a loss of melanin pigment from the epithelial plates. Orcein (elastic) stain highlighted an increase of the number of the elastic fibers surrounding the tumor. On the basis of these findings, a diagnosis of eruptive TFI was established for both cases. Among the various presentations of TFI, only the eruptive variant appears to be clinically distinctive, with asymptomatic hypopigmented macules usually located on the face, neck and upper trunk. Eruptive TFI should also be added to the clinical differential diagnosis of multiple hypopigmented macules on the buttocks of Black patients.

Cryopyrin-associated periodic syndrome: an autoinflammatory disease manifested as neutrophilic urticarial dermatosis with additional perieccrine involvement.

A female newborn presented with a congenital urticarial rash that consisted of fluctuating well-demarcated pink or pale reddish macules or slightly raised papules and plaques. In addition, purulent cerebrospinal fluid was present in the absence of evidence of congenital infection. Skin biopsy revealed a sparse infiltrate throughout the entire dermis, including the eccrine adventitia. The infiltrate was composed mostly of neutrophils, but rarely lymphocytes and eosinophils could also be seen. No vasculitis was present. Because of the presenting attributes, a diagnosis of cryopyrin-associated periodic syndrome (CAPS) was considered and the neonatal-onset multisystem inflammatory disorder (NOMID) that represents the most severe expression of the CAPS clinical spectrum was favored. Diagnosis was confirmed by identification of a mutation in the cold-induced autoinflammatory syndrome-1 gene and by an observed response to treatment with the interleukin-1 receptor antagonist anakinra. Both the clinical and histopathological findings of the presented case may represent a distinct entity within the spectrum of aseptic neutrophilic dermatitis. We refer to this spectrum as neutrophilic urticarial dermatosis (NUD), which may serve as a cutaneous marker of autoinflammation. NUD with perieccrine involvement should prompt consideration of CAPS, especially NOMID, in the context of neonatal multisystem disease.

Revisiting nephrogenic systemic fibrosis in 6 kidney transplant recipients: a single-center experience.

BACKGROUND: Nephrogenic systemic fibrosis (NSF) is a fibrotic disorder occurring in patients with renal dysfunction. Exposure to gadolinium (Gd)-based contrast agents (GBCAs) during renal impairment is associated with development of NSF. METHODS: A cross-referenced search of kidney transplantation and radiology databases at a single institution revealed the prevalence of NSF in the transplant population. Clinical records and skin biopsy specimens from 6 patients with kidney transplant given a diagnosis of NSF were reviewed to identify contributing factors. RESULTS: Between January 1999 and December 2006, NSF was diagnosed in 6 of 705 patients with kidney transplant (0.9%). Renal function was impaired in all patients. Of 33 patients with kidney transplant exposed to GBCAs, 5 (15.2%) developed NSF. Disease onset ranged from 7 days to 11 months after exposure to GBCAs. All 5 patients exposed to GBCAs who developed NSF were also treated with a beta-blocker and clinical improvement was observed with discontinuation. The sixth case NSF appeared unrelated to Gd, without a known exposure, and testing of tissue via mass spectrometry revealed no Gd. Symptoms of NSF in this patient disappeared after administration of darbepoetin was switched from subcutaneous to intravenous injection. One patient with NSF who manifested the highest Gd level in tissue died 22 months after disease onset. LIMITATIONS: The study represents the retrospective experience of only a single center. CONCLUSIONS: NSF can develop in kidney transplant recipients with altered graft function. In these patients, exposure to GBCAs appears associated with development of NSF. The role of beta-blockers in the course of the disease merits further investigation.

Acantholytic tumor of the nail: acantholytic dyskeratotic acanthoma.

Acantholytic dyskeratotic acanthomas of the skin have been recently described in several publications. They differ from acantholytic acanthomas by the presence of dyskeratosis. However these tumors have never been described in nails. We report three cases localized on the thumb nail.

Congenital disseminated juvenile xanthogranuloma with unusual skin presentation and renal involvement.

We present a case of congenital juvenile xanthogranuloma (JXG) with both cutaneous and renal involvement. Skin lesions consisted of bluish papules and nodules (blueberry muffin baby) located on the head, trunk and proximal extremities. Subsequent investigations revealed a renal mass. Histopathology of both cutaneous and renal specimens was consistent with JXG. Both clinical presentation and extracutaneous localization were remarkable.

Thalidomide in refractory vulvar ulcerations associated with Crohn's disease.

We report a case of recurrent vulvar ulcerations developed on vegetations associated with Crohn's disease. Lesions responded to low-dose thalidomide treatment. A biopsy revealed a neutrophilic infiltrate with rare giant cells. Vulvar manifestations were consistent with metastatic Crohn's disease or with a reactive neutrophilic dermatitis. Thalidomide reduces the activity of tumor necrosis factor (TNF) alpha by accelerating the degradation of its mRNA. Nowadays, it has become a promising drug in a broad variety of disorders in which TNF-alpha seems to play a pivotal role, including inflammatory bowel diseases. This is the first case report presenting the efficacy of thalidomide in the treatment of vulvar involvement in Crohn's disease.

POEMS syndrome revealed by multiple glomeruloid angiomas.

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin disorders) is a rare multisystemic disease associated with plasma cell dyscrasia. A 68-year-old woman with chronic renal insufficiency and arterial hypertension included in her medical history was admitted to the hospital with confusion, somnolence and asthenia. She presented ascites, hepatosplenomegaly, leg oedema, distal dysesthesias, leuconychia and multiple nodular purple red angiomas on the trunk, upper limbs and fingers. Hypothyroidism was revealed in the laboratory investigations and monoclonal IgG peak in immunoelectrophoresis. Electromyography showed both demyelinisating and axonal degenerative neuropathy. The diagnosis of POEMS syndrome was based on the dermatopathological examination of a cutaneous angioma; histology revealed features of glomeruloid angioma, a specific marker of this syndrome.