BACKGROUND: Congo red staining of fat pad fine needle aspiration specimens is a method utilized for evaluation of amyloid deposition. However, these specimens can pose diagnostic challenges for cytopathologists. As part of ongoing internal quality improvement measures, the objective of this study was to evaluate the intradepartmental interobserver agreement of these specimens and to identify factors that affect the variability of the interpretations.
METHODS: There were 7 participants, which included 3 trainees, 3 cytopathologists, and 1 cytotechnologist. Each participant reviewed 50 Congo red stained fat pad fine needle aspiration slides. The interpretations were categorized into 3 groups: negative, indeterminate/suspicious, and positive. The participants also noted any interpretation challenges they encountered for each case.
RESULTS: There was only slight interobserver agreement among all participants (κ = 0.133). Stratified by participant group, the interobserver agreement among the trainees was slight bordering on poor (κ = 0.028) and among cytopathologists was fair (κ = 0.249). The highest agreement between 2 observers was between 2 cytopathologists and the level of agreement was moderate bordering on fair (κ = 0.426). There were only 3 cases (6.0%) with full agreement among observers, while in 25 cases (50.0%), there were 2 category differences in interpretations. The primary diagnostic challenge reported by participants was when weak or focal birefringence was encountered as well as cases complicated by poor stain quality and overstaining.
CONCLUSIONS: We found only slight interobserver agreement among all study participants. A major area of challenge was cases with weak birefringence resulting in high variance of interpretation among participants.

Although AA amyloidosis is primarily caused by inflammatory conditions, associations between AA amyloidosis and solid cancers have occasionally been described. Herein, we report the case of a 48-year-old man in whom resection of a proliferating pilomatricoma with deposition of AA amyloid resulted in remission of concomitant AA gastrointestinal amyloidosis. A rapidly growing, giant, reddish, ulcerated tumor measuring 16 × 13 cm in size was identified on the upper left arm on a visit to our hospital. Gastrointestinal AA amyloidosis was diagnosed from colorectal mucosal biopsy at the same time, and weight loss and profuse diarrhea were clinically evident. As treatment, the tumor was resected with a 10-mm surgical margin. Histologically, the tumor predominantly comprised a lobular proliferation of basophilic cells peripherally, filled with eosinophilic, cornified material and shadow cells with mitoses observed in basophilic cells. Specimens revealed eosinophilic, homogeneous deposits around tumor nests, which were confirmed as amyloid deposits by positive staining with Congo red stain. These deposits were immunohistochemically positive on staining with anti-serum amyloid A antibody. Collectively, proliferating pilomatricoma with AA amyloidosis was diagnosed. After tumor resection, chronic diarrhea resolved and no amyloid deposition was apparent in colorectal biopsy. It is important to remember that if amyloid deposition is present in a tumor, aggressive tumor excision may alleviate systemic amyloidosis.

BACKGROUND: Fine-needle aspiration (FNA) of abdominal fibroadipose tissue is a commonly utilized method for the detection of amyloidosis. While generally regarded as an accurate and specific detection method, the sensitivity is variable. The objective of this study was to investigate the performance of fat pad FNAs in detecting amyloidosis relative to other tissue biopsies.
METHODS: Fat pad FNA results from January 1, 2014, to December 31, 2022, were catalogued. Clinical data including FNA indication were ascertained for each case. The results of any subsequent tissue biopsy/biopsies evaluated for amyloidosis by Congo red staining were also assessed. Challenges to diagnostic interpretation were explored.
RESULTS: A total of 334 fat pad FNAs were identified. The most common indications were peripheral neuropathy (29.3%), cardiomyopathy/heart failure (28.1%), monoclonal gammopathy (27.8%), and multiple myeloma/lymphoplasmacytic lymphoma (21.0%). Cytologic interpretations were: 7 (2.1%) nondiagnostic, 284 (85.0%) negative, 18 (5.4%) indeterminate, 16 (4.8%) suspicious, and 9 (2.7%) positive for amyloid deposition. In our sample, 103 (30.8%) patients had Congo red testing performed on a subsequent surgical specimen(s) including: 3 of 7 of nondiagnostic cases, none which were positive on the subsequent surgical; 70 of 284 negative cases, 27 which were positive on the subsequent surgical; 11 of 18 indeterminate cases, 7 which were positive on the subsequent surgical; 13 of 16 suspicious cases, 2 which were positive on the subsequent surgical; and 6 of 9 positive cases, 3 which were positive on the subsequent surgical. Challenges to FNA interpretation included scant cellularity, focal staining/birefringence, and overstaining.
CONCLUSIONS: It is best to view fat pad aspiration versus other tissue biopsy results as complimentary diagnostic tests that should be interpreted in the context of the clinical setting and overall clinical suspicion for amyloidosis.

Primary systemic amyloidosis is generally a systemic condition and only a few of systemic amyloidosis cases manifest with signs of single-organ involvement. The occurrence of symptoms and signs of hepatic involvement alone in primary systemic amyloidosis is rare, presenting a diagnostic challenge. In this case, a 55-year-old lady presented with nonspecific symptoms such as weight loss and loss of appetite. She was found to have mildly deranged liver function tests with a cholestatic pattern, and there were no apparent risk factors for liver disease. Clinical features of involvement in other organs were notably absent. After ruling out common causes of cholestatic liver disease, we considered the possibility of infiltrative liver disease and arranged for a liver biopsy, which revealed the diagnosis of amyloidosis. In summary, while hepatic deposition is a relatively common consequence of systemic amyloidosis, it is exceptionally rare for a patient to present with clinical features of liver involvement alone. This rarity presents a significant diagnostic challenge. Given the infrequency of this presentation, a diagnosis of amyloidosis should be considered only after diligently excluding other more common causes of hepatomegaly, whether associated with abnormal liver function tests or not.

Amyloidosis is a disease caused by amyloid deposition in tissues or organs. According to the extent of the lesion, it can be divided into systemic amyloidosis and localized amyloidosis. Amyloidosis originating in the larynx accounts for approximately 0.5% to 1.0% of benign lesions of the larynx; such lesions are relatively rare and mostly localized. Nasopharyngeal amyloidosis combined with laryngeal amyloidosis is even rarer. We herein present a case involving a patient with amyloidosis in the nasopharynx and larynx who presented with a foreign body sensation and hoarseness in the pharynx. Electronic fiber laryngoscopy revealed a smooth neoplasm in the left nasopharynx and left vocal cord. The patient underwent surgical treatment, and the postoperative pathologic examination results suggested amyloidosis. Special staining performed using Congo red and crystal violet was positive, confirming amyloidosis. The patient recovered after surgery, and no recurrence was present at the 3- and 6-month follow-ups.

Primary amyloidosis is a rare condition with 6-10 cases in a million, with focal involvement representing 9%-15% of those cases [1,2]. Isolated tracheobronchial amyloidosis is extremely rare and when present, can result in focal or diffuse thickening of the glottis, trachea and bronchi, leading to hoarseness, shortness of breath, and dysphonia. Computed tomography (CT) usually shows circumferential thickening of trachea and bronchi with or without calcifications and associated airway narrowing of affected segments. MRI demonstrates intermediate to low signal on T1, low signal on T2 and variable heterogeneous enhancement. Multiple conditions can result in thickening of the airway including but not limited to inflammatory, infectious, and neoplastic etiologies. Biopsy with histologic correlation provides a definitive diagnosis. Biopsied tissue demonstrates characteristic apple-green birefringence with Congo red stain. There is no cure for amyloidosis and the prognosis is quite variable depending on the extent of airway involvement. Current treatments are aimed at alleviating symptoms and include bronchoscopic debridement, laser therapy, and balloon dilation with adjuvant radiation therapy. Here, we present a rare case of a 47-year-old male with isolated laryngotracheal amyloidosis with marked airway narrowing and vocal fold involvement.

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Fat pad aspiration is a commonly used method for detecting amyloid in tissue. Amyloid is detected in the small blood vessels of the aspirated adipose tissue. Optimum evaluation of amyloid with electron microscopy requires at least 15 blood vessels in the fat pad aspirate. The presence of a significant proportion of adipocytes in the aspirate dilutes the fibrovascular portion. This may compromise the evaluation for amyloid with electron microscopy and in FFPE with proteomic studies by mass spectroscopy for confirmation of the amyloid subtype. This video article describes the updated protocol for processing the anterior fat pad aspirate. It demonstrates how to remove the interference of blood and fatty component in the fat pad aspirate performed by the previously reported procedure.

A 35-year-old woman with progressive decrease of vision in both eyes and with no other associated symptoms, manifested as the only antecedent, the death of her brother due to amyloidosis. The visual acuity was counting fingers at 30 centimetres in the right eye and 20/70 in the left eye. In ophthalmoscopy of the right eye, a white, homogeneous vitreous, that was difficult to assess in detail, was observed, and in the left eye a whitish vitreous with band-like opacities in the cortical region. Vitrectomy was performed in the right eye, and a study with specific stains showed positive for amyloid material. A case is reported of amyloidosis diagnosed with specific stains in a vitreous sample for which the initial and only manifestation was the presence of vitreous opacities. The processing of these samples should be considered in patients with family history, early vitreous opacities, negative results of systemic biopsy, or atypical course of the disease.

UNASSIGNED: Inflammation in tumor microenvironment assists in both promotion and growth of tumor. Tumor-associated tissue eosinophilia (TATE) is the term used when eosinophils are observed in a tumor tissue with inflammatory infiltrate. Although carcinogenesis with inflammation is one of the important hallmarks, the exact role of eosinophils remains unclear. Various studies on oral squamous cell carcinoma (OSCC) that focused on eosinophils reported both favorable and unfavorable prognosis in cancer tissue, because of which the exact function of eosinophils still remains uncertain.
UNASSIGNED: The present study aims at identifying the role of TATE in OSCC and in malignant transformation of oral epithelial dysplasia (OED).
UNASSIGNED: The study includes 70 samples that divided into two groups, of which 50 histopathologically proven cases of different grades of OSCC and 20 cases of OED (oral leukoplakia). Congo red stain was used to stain the tissue sections. Each slide was viewed under high power in 10 consecutive microscopic fields for counting of eosinophils.
UNASSIGNED: Statistical analysis of values obtained was done using ANOVA, unpaired t-test and Mann-Whitney test. The results were statistically significant (P < 0.05) with a mean total eosinophil count of 2.12 in OED and 4.31 in OSCC.
UNASSIGNED: The present study showed higher eosinophil counts in OSCC when compared to dysplasia which should prompt for a thorough evaluation of tumor front for invasiveness. Therefore, tissue eosinophil count may be used as an adjunct to predict the malignant transformation of dysplastic lesions to OSCC.