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We present the case of a 10-year-old boy who was admitted with 3 months of episodic febrile neutropenia and a new petechial rash. Routine bloods identified neutropenia, thrombocytopenia, and a raised alanine aminotransferase. The dermatology team was consulted in light of the symmetrical petechial eruption of the upper torso. A punch biopsy of the lesion was consistent with early capillaritis. The results showed superficial dermal red blood cell extravasation with mild perivascular lymphohistiocytic inflammatory infiltrate. There was no evidence of an atypical lymphoid infiltrate in the skin biopsy. An initial bone marrow aspirate showed an abnormal mature T-cell population consisting of CD4 and CD8 T cells with gamma-delta positivity. Karyotyping was also done, which demonstrated isochromosome 7q. These findings were consistent with a diagnosis of hepatosplenic T-cell lymphoma (HSTL). The patient underwent fourth-line chemotherapy due to refractory relapsing disease but sadly passed away within 12 months of diagnosis. HSTL is a rare and aggressive subset of peripheral T-cell lymphoma. Prognosis is poor with a median survival of1 year from diagnosis. However, reports suggest improved outcomes if intensive, early, high-dose chemotherapy is used alongside hematopoietic stem cell transplantation. Therefore, there is an impetus to attain early diagnosis for aggressive early treatment and improved patient outcomes. Capillaritis, presenting as asymptomatic nonpalpable purpura, can be a rare presenting feature of HSTL. Dermatologists could play a pivotal role in the early recognition of this rare but aggressive hematological malignancy and promote prompt treatment resulting in better patient outcomes.

Introduction: Mucocele-like lesions (MLL) of the breast are rare entities which are considered to harbor uncertain malignant potential. Current UK guidelines recommend vacuum assisted excision (VAE) of all such lesions regardless of whether they display epithelial atypia. This study sought to review the key histological and radiological features of MLLs and compare their differing outcomes based on the presence of epithelial atypia. Methods: Pathology records of a single breast cancer screening center were retrospectively searched for all biopsy diagnosed MLLs over an 11-year period. Upgrade rates to malignancy (positive predictive values) were calculated by reviewing histology from the initial core biopsy and comparing with the corresponding excision specimen. Radiological images were simultaneously reviewed to provide radiological-pathological correlation. Results: Three of 11 patients (27.3%) with atypical MLLs on biopsy had malignant outcomes at excision, compared with only 1 of 36 patients (2.8%) with non-atypical MLLs. The majority of MLLs (93%) were identified as microcalcifications on mammographic imaging. No specific radiological features were predictive of malignancy. Conclusions: Our data suggest that MLLs without atypia are potentially overtreated with current protocols and could be managed conservatively with radiological follow up. Radiological-pathological correlation is essential.

Background B3 breast lesions are a heterogeneous group with uncertain malignant potential and, as such, provide a source of diagnostic difficulty. We calculated the prevalence of B3 lesions at our center along with the upgrade rates (positive predictive value) to in situ or invasive malignancy. Materials and Methods We searched our pathology database over a 3-year period to include all B3 biopsies. The subsequent excision for each biopsy was reviewed, and the rate of upgrade was calculated by subtype. These results were compared against data published in large United Kingdom studies. Results A total of 9206 breast biopsies were identified, of which 614 (6.7%) were classified as B3. Lesions displaying epithelial atypia were the most common subtype of lesion, with a prevalence of 39.6%. Lesions displaying epithelial atypia were upgraded to malignancy in 35.7% of cases. Among non-atypical cases, papillary lesions were the most common diagnosis (32.1%) with an upgrade rate of 2%. In situ lobular neoplasia (10.4%) was the third most frequently encountered diagnosis, and was upgraded to malignancy in 10.9% of cases. The upgrade rate in the remaining non-atypical lesions was invariably low (0%-2.6%). Conclusions Herein, we have shown an overall B3 rate in keeping with published data, whereas lesions displaying epithelial atypia showed upgrade rates to malignancy comparable with that of large United Kingdom studies. In our study, lesions without epithelial atypia showed very low rates of upgrade. A wide range of upgrade rates is seen in cases of lobular neoplasia, which highlights the need for uniformity of nomenclature and reporting within this subtype to accurately ascertain the true risk of upgrade associated with these lesions.

Methylene blue is a chromophore dye known for its photosensitizing properties. It is also administered intravenously as a tracer in parathyroid surgery to identify abnormal glands. We describe 2 cases of acute methylene blue-induced phototoxicity in patients who underwent parathyroidectomy. Both patients developed an acute vesiculopustular inflammatory rash on the anterior neck corresponding to the site exposed intraoperatively to overhanging surgical lights. One of the patients also developed a bulla on her finger at the site of attachment of the oxygen probe. Biopsies were taken from both patients at different time points. The histological findings included destruction of sebaceous glands and deposition of diastase-periodic acid-Schiff-positive hyaline material around dermal blood vessels. These features are similar to those seen in skin treated with photodynamic therapy and systemic photosensitivity disorders such as the porphyrias. The wavelengths of light emitted by the surgical lights and oxygen probe overlap with the absorption spectrum of methylene blue. This resulted in excitation of the systemically administered methylene blue at exposed sites, with resultant local tissue damage and a phototoxic reaction.

Moonim M T, Alarcon L, Freeman J, Mahadeva U, van der Walt J D & Lucas S B (2010) Histopathology56, 530–541 Identifying HIV infection in diagnostic histopathology tissue samples – the role of HIV-1 p24 immunohistochemistry in identifying clinically unsuspected HIV infection: a 3-year analysis Aims: Because of the clinical difficulty in identifying the early stages of human immunodeficiency virus (HIV) infection, the histopathologist often has to consider the diagnosis of HIV in tissue samples from patients with no previous suspicion of HIV infection. The aim was to investigate the practicality and utility of routine HIV-1 p24 immunohistochemistry on tissue samples received at a London histopathology laboratory. Methods and results: Over a 3-year period, HIV-1 p24 was evaluated immunohistochemically on 123 cases. Of these, 37 (30%) showed positive expression of p24 in lesional follicular dendritic cells (FDCs). Of these 37 cases, 11 were not clinically suspected to be HIV+ and had no prior serological evidence of HIV infection. These cases represented lymph node biopsies, tonsillar and nasopharyngeal biopsies and a parotid excision. In addition to expression on FDCs, in 22 cases (60%), p24 also highlighted mononuclear cells and macrophages. p24 was also useful in confirming the presence of HIV in lymphoid tissue in non-lymphoid organs such as the lung, anus, salivary gland and brain. Immunonegativity occurred in occasional known HIV+ cases, probably related to treatment or tissue processing. Conclusions: This study confirms the usefulness of this technique in detecting unsuspected HIV infection in lymphoid and non-lymphoid organs on histopathological material and should be part of routine evaluation of lymph nodes and lymphoid tissue in other organs if morphological or clinical features suggest HIV infection.

This study aimed to clarify whether positive temporal artery biopsies had a greater sample length than negative biopsies in temporal arteritis. It has been suggested that biopsy length should be at least 1 cm to improve diagnostic accuracy. A retrospective review of 149 patients who had 151 temporal artery biopsies was conducted. Twenty biopsies were positive (13.3%), 124 negative (82.1%) and seven samples were insufficient (4.6%). There was no clinically significant difference in the mean biopsy size between positive (0.7 cm) and negative samples (0.65 cm) ( t-test: p = .43 NS). Ninety-four patients fulfilled all three ACR criteria prior to biopsy (62.3%) and four patients (2.6%) changed ACR score from 2 to 3 after biopsy. Treatment should not be delayed in anticipation of the biopsy or withheld in the case of a negative biopsy if the patient’s symptoms improve.

An illustration of the diagnosis and management of tailgut cysts. Two cases of tailgut cyst and a review of the literature. A female patient presented with acute urinary retention with a retrorectal mass felt during rectal examination and confirmed on ultrasound and magnetic resonance imaging underwent surgical resection and histology confirmed a chronically inflamed mucoid fluid-filled cyst partly lined by non-keratinised squamous epithelium. A male patient with ureteric obstruction and a prerectal cyst found on ultrasound scan underwent computed tomography with biopsies, but without reaching a conclusive diagnosis. Surgical resection was carried out and histology showed a chronically inflamed mucoid fluid-filled cyst partly lined with columnar epithelium. Tailgut cysts are a rare developmental abnormality arising from remnants of the embryological postanal gut. Usually presenting incidentally or with pressure symptoms in middle-aged females, tailgut cysts are often initially mistaken for other clinical entities. Magnetic resonance imaging helps to differentiate tailgut cysts from other retrorectal lesions and developmental cysts. Histologically, the cyst wall demonstrates a wide variety of epithelial types and has a malignant potential. Malignancy is difficult to rule out with imaging or biopsy. Magnetic resonance imaging is the favoured imaging modality and surgical resection is recommended to relieve pressure symptoms, provide a definitive diagnosis and rule out malignancy.