Primary Cilia as a Tumor Marker in Pituitary Neuroendocrine Tumors.

Pituitary neuroendocrine tumors (PitNETs) account for approximately 15% of all intracranial neoplasms. Although they usually appear to be benign, some tumors display worse behavior, displaying rapid growth, invasion, refractoriness to treatment, and recurrence. Increasing evidence supports the role of primary cilia (PC) in regulating cancer development. Here, we showed that PC are significantly increased in PitNETs and are associated with increased tumor invasion and recurrence. Serial electron micrographs of PITNETs demonstrated different ciliation phenotypes (dot-like versus normal-like cilia) that represented PC at different stages of ciliogenesis. Molecular findings demonstrated that 123 ciliary-associated genes (eg, doublecortin domain containing protein 2, Sintaxin-3, and centriolar coiled-coil protein 110) were dysregulated in PitNETs, representing the upregulation of markers at different stages of intracellular ciliogenesis. Our results demonstrate, for the first time, that ciliogenesis is increased in PitNETs, suggesting that this process might be used as a potential target for therapy in the future.

Pancreatic panniculitis revisited: A series of 34 patients.

BACKGROUND: Pancreatic panniculitis is a rare form of panniculitis generally associated with acute or chronic pancreatitis, and less frequently with pancreatic carcinoma. Clinically, it presents with subcutaneous nodules usually located in the lower extremities, however, it presents an almost pathognomonic histopathological finding with enzymatic fat necrosis in the adipose tissue. METHODS: In this retrospective case series of five hospitals, biopsy specimens of cutaneous lesions of pancreatic panniculitis were reviewed. Clinical information was obtained through medical records. RESULTS: A total of 34 cases were included, 23 women and 11 men, aged between 31 and 92 years. The most common associated pancreatic disease was acute pancreatitis (23 cases) and its main triggering cause was gallstones (17 cases). In two patients it was related to chronic pancreatitis and six cases were associated with malignancy. Histopathological findings were always the key to diagnosis. In the biopsies reviewed, mostly lobular panniculitis with the characteristic necrosis of the adipocytes was observed. In addition, nine of the cases presented with Splendore-Hoeppli phenomenon. CONCLUSIONS: We present the largest series of pancreatic panniculitis. Clinically, the female predominance and biliary lithiasis as the main cause of acute pancreatitis are to be emphasized. Histopathologically, a peripheral eosinophilic striated rim surrounding aggregates of ghost adipocytes consistent with Splendore-Hoeppli is an additional clue to its diagnosis.

Cutaneous vascular calcification. Perieccrine calcification as a diagnostic key for calciphylaxis.

BACKGROUND: Attempts have been made to establish discriminative criteria between classic calciphylaxis (CPX) and those cases in which cutaneous vascular calcification (CVC) represents an incidental finding (epiphenomenon). METHODS: Retrospective, observational cohort study of patients with CVC to distinguish clinicopathological features between CVC as classic CPX (CVC in cutaneous lesions with erythematous-violaceous plaques with or without ulceration) or as an epiphenomenon (CVC in cutaneous lesions with known diagnosis). Different clinicopathological parameters and the presence of perieccrine calcification and pseudoxanthoma elasticum (PXE)-like changes were evaluated. RESULTS: Sixty-six patients were studied. The CPX group showed a significantly higher percentage of renal failure, hypertension, altered laboratory parameters, painful lesions, and mortality rate. Histopathologically, the CPX group was associated with more than one vessel per field involved with subintimal concentric calcification and perieccrine calcification (observed exclusively in the CPX group), while PXE-like changes, although more frequent in the CPX group, were also observed in the epiphenomenon group. CONCLUSION: Perieccrine calcification and the presence of more than one vessel per field involved by concentric pattern calcification could be used as a diagnostic marker of CPX. Although PXE-like changes are not an exclusive marker, they could suggest CPX diagnosis.

Graft-versus-host disease-associated angiomatosis with striking lipomatous metaplasia.

Sclerodermatous graft-versus-host disease (GvHD) is one of the many clinicopathological variants of chronic GvHD. One of the rarest forms of this variant is GvHD-associated angiomatosis (GvHD-AA). We describe the case of a 62-year-old male with sclerodermatous GvHD who presented, in consecutive years, two different lesions that showed characteristics of GvHD-AA. The first lesion fitted perfectly with the previously known features of this rare entity. However, the second lesion was more interesting, as the angiomatoid lesion was surrounded by newly appeared adipocytes, something not previously described. The appearance of this peculiar adipose tissue may be explained as related to an important dermal atrophy, as a concomitant appearance of a lipomatous nevus and GvHD-AA, or, finally, as mature adipose tissue related to a previous inflammatory process, that is, lipomatous metaplasia. Both lesions were diagnosed as GvHD-AA, and the second one was considered to be associated with dermal lipomatous metaplasia. We also considered whether hypoxia could be related to both lesions. In the present report, we review previously published cases of GvHD-AA and discuss the different hypotheses that could explain the appearance of metaplasia associated with the second lesion.

Increased number of pulmonary megakaryocytes in COVID-19 patients with diffuse alveolar damage: an autopsy study with clinical correlation and review of the literature.

Pulmonary megakaryocytes participate in the pathogenesis of lung damage, particularly in acute lung injury. Although megakaryocytes are not mentioned as a characteristic histologic finding associated to pulmonary injury, a few studies reveal that their number is increased in diffuse alveolar damage (DAD). In this autopsy study, we have observed a relevant number of pulmonary megakaryocytes in COVID-19 patients dying with acute lung injury (7.61 ± 5.59 megakaryocytes per 25 high-power fields vs. 1.14 ± 0.86 for the control group, p < 0.05). We analyzed samples of 18 patients, most of whom died after prolonged disease and use of mechanical ventilation. Most patients showed advanced DAD and abnormal coagulation parameters with high levels of fibrinogen, D-dimers, and variable thrombocytopenia. For comparison, pulmonary samples from a group of 14 non-COVID-19 patients dying with DAD were reviewed. They showed similar pulmonary histopathologic findings and an increase in the number of megakaryocytes (4 ± 4.17 vs. 1.14 ± 0.86 for the control group, p < 0.05). Megakaryocyte count in the COVID-19 group was greater but did not reach statistical significance (7.61 ± 5.59 vs. 4 ± 4.17, p = 0.063). Regardless of the cause, pulmonary megakaryocytes are increased in patients with DAD. Their high number seen in COVID-19 patients suggests a relation with the thrombotic events so often seen these patients. Since the lung is considered an active site of megakaryopoiesis, a prothrombotic status leading to platelet activation, aggregation and consumption may trigger a compensatory pulmonary response.

Neutrophilic Infiltrates in Panniculitis: Comprehensive Review and Diagnostic Algorithm Proposal.

Neutrophilic infiltrates in panniculitis can be seen in different clinical-pathological entities. There are a "mostly neutrophilic inflammatory infiltrate" in some entities classically defined as neutrophilic panniculitis and already included in algorithms, such as enzymatic panniculitis, infective and factitial ones, erythema induratum, or subcutaneous Sweet syndrome, but there are also other panniculitis where neutrophils are frequently observed such as panniculitis associated with inflammatory bowel disease or rheumatoid arthritis, or drug-induced panniculitis associated with BRAF inhibitors, and finally, some panniculitis are better classified in other panniculitides groups but may present with neutrophil-rich variants, such as the neutrophil-rich subcutaneous fat necrosis of the newborn. We review the main clinical and histopathological features of most of these panniculitides and construct a diagnostic algorithm including these diseases.

Bullous pemphigoid associated with dipeptidyl peptidase-4 inhibitors. A case series and analysis of cases reported in the Spanish pharmacovigilance database.

BACKGROUND: Bullous pemphigoid (BP) has been associated with dipeptidyl peptidase-4 inhibitors (DPP4i). Clinical features, outcomes, and risk of BP for new DPP4i (linagliptin, saxagliptin, and alopgliptin) are not well established. Comparison of risk of BP appearance for DPP4i and other oral antidiabetic drugs (OADs) such as sodium glucose cotransporter 2 inhibitors has not been studied to date. OBJECTIVES: To describe the prevalence, sociodemographic, clinical, and histopathological characteristics, and outcome after drug withdrawal in DPP-4i-associated BP cases from our hospital. To review all Spanish spontaneous notifications of BP where DPP4i or OADs were included as suspected drugs and calculate the reporting odds ratios (RORs). METHODS: A retrospective observational study was performed examining the association between DDP4i and BP. Clinical features and RORs were analyzed. Data from the Spanish Pharmacovigilance System (SEFV) are included. RESULTS: In our center, 28 of 89 patients with BP (31.5%) were under DPP4i treatment; 53.6% were male, and mean age was 80.8 years. BP debuted the first year after DPP4i in 57.2%. BP control was achieved within 3.7 months after drug withdrawal. Regarding SEFV, 22 of 972 spontaneous notifications were related to BP and DPP4i. RORs were superior for DPP4i compared to other OADs. Vildagliptin had the highest ROR. CONCLUSIONS: We present the largest DPP4i-induced BP case series in a single center, with a detailed study of the sociodemographic, clinical, and histopathological characteristics of each patient, and their treatment and outcome. Vildagliptin had the highest risk. DPP4i-associated BP does not seem to have specific clinical characteristics.

Bilateral Facial Apocrine Fibrosing Hamartoma Mimicking Microcystic Adnexal Carcinoma.

An otherwise healthy 50-year-old woman was evaluated for the presence of 2 erythematous, and slightly pruritic plaques, involving both cheeks for 30 years. Left-side skin biopsy showed a diffuse proliferation of ductal structures horizontally arranged and involving the reticular dermis that resembled tubular adenoma embedded in a sclerotic stroma and surrounded by a peculiar periductal desmoplasia. Nuclear atypia or mitosis was not found. Contralateral biopsy showed identical findings. Differential diagnosis included microcystic adnexal carcinoma (MAC) and plaque-like syringoma and a peculiarly horizontally arranged tubular adenoma. We ruled out MAC as the lesions were long-standing, without infundibular cysts, solid strands, or perineural infiltration. Our case closely resembled those previously described as sweat duct proliferation associated with aggregates of elastic tissue and atrophoderma vermiculatum, although striking differences were observed, as our case did not present aggregates of elastic tissue, did not involve the papillary and superficial reticular dermis, and presented evidences of decapitation secretion as a sign of apocrine differentiation. We consider our case as a MAC simulator and we propose the descriptive name of bilateral facial apocrine fibrosing hamartoma.

Immunohistochemical Study of 2 Cases of Coxsackie A6-Induced Atypical Hand-Foot-and-Mouth Disease.

An atypical clinical variant of hand-foot-and-mouth disease (HFMD) with more extensive lesions and affecting adults has emerged during the past years, usually associated to the Coxsackievirus serotype A6 (CV-A6). We present a 19-year-old woman with a 3-day evolution eruption of papulovesicular lesions, which first appeared around the mouth and frontal area and rapidly spread. In addition, we present a 61-year-old man with a 4-day evolution asymptomatic eruption of papulovesicular lesions in both the hands and feet after suffering a cold 1 week before. Skin biopsies of both patients showed intraepidermal vesicles with spongiosis and ballooning, leading to reticular degeneration, apoptotic keratinocytes, and epidermal necrosis of the upper layers with neutrophil sloughing. Immunohistochemical studies for Coxsackie, Enterovirus, herpes virus, adenovirus, and measles were all negative. Cultures of blister fluid, reverse transcription polymerase chain reaction of skin biopsies, blood tests and serologies for exanthematic virus, and serum viral arrays were also negative. Only reverse transcription polymerase chain reaction of blister fluid confirmed Cocksakie A6. In conclusion, immunohistochemical studies with the commercially available viral antibodies do not seem to be useful in atypical HFMD cases. In these cases, to determine the typical histopathological features in HE is the fastest diagnostic aid.