The spectrum of malignant diagnoses in cerebrospinal fluid cytology from an adult population: a multi-institutional retrospective review.

INTRODUCTION: Limited updated literature exists about the prevalence and spectrum of malignancies involving cerebrospinal fluid (CSF). In this multi-institutional study, we review our experience with focus on first time malignancy diagnosis in CSF samples of adults. MATERIALS AND METHODS: Institutional databases at 4 academic centers were queried retrospectively for CSFs over a 10-year period. The following data elements were collected: total # of CSFs, total # of CSFs with a malignant diagnosis; for each patient with a first time CSF diagnosis of malignancy: age, gender, diagnosis, prior history of malignancy, and ancillary studies. RESULTS: Twenty-four thousand one hundred forty-two CSFs were collected with a positive for malignancy rate of 2.3% (n = 551). Out of 347 (1.4%) adults with a first-time diagnosis of CSF malignancy 182 (52%) were female (age range: 19-89/mean: 57) and 165 (48%) were male (age range: 20-95/mean: 60). Hematolymphoid malignancies (48%, n = 168) were overall the most common neoplasm. In women, metastatic carcinomas (63%, n = 114) were the leading malignancy, of which the majority were breast primaries. In men, lymphomas/leukemias (64%, n = 106) were the leading malignancy, of which the majority were B-cell lymphomas. Ancillary studies aided the final diagnosis in 110 (32%) cases. For 286 (82%) cases, a prior history of malignancy was available to correlate CSF findings. CONCLUSIONS: A malignancy diagnosis in the CSF of adults is rare. The most common malignancies in females and males are metastatic breast carcinoma and hematolymphoid malignancies, respectively. Metastatic neoplasms account for the majority, with primary central nervous system neoplasms being quite uncommon. History of malignancy and ancillary tests can be helpful.

Colorectal Carcinoma With Sarcomatoid Components: Report of 15 Cases and Literature Review of an Exceedingly Rare Carcinoma Subtype.

Colorectal carcinoma with sarcomatoid components (which includes so-called carcinosarcomas and sarcomatoid carcinomas) is a rare subtype with 50 reported cases in the literature and overlapping criteria with undifferentiated carcinoma. We collected and described 15 cases from 10 men and 5 women, with a mean age of 66 years. Symptoms included abdominal pain and gastrointestinal bleeding. Most tumors presented in the rectosigmoid region, with a mean size of 8.2 cm. The sarcomatoid component, on average, represented 58% of the tumors and took many forms, including spindled (10 cases), anaplastic (9 cases), and rhabdoid (3 cases); one case showed osteoid matrix. Tumor budding was usually high, and tumor-infiltrating lymphocytes were usually low. The sarcomatoid component was keratin-positive in 10 cases. One case showed loss of mismatch repair protein expression, and 2 cases showed SMARCA4 loss (1 also with SMARCA2 loss). Molecular testing identified mutations in KRAS (n=1), NRAS (n=2), BRAF (n=2), APC (n=1), and TP53 (n=1) in a few cases. Tumors often presented at advanced stage, with 11 cases pT4, 9 cases with nodal metastases, and 7 cases with distant metastases. Follow-up was available for 10 cases (median: 2 months), with 2 alive without disease, 3 alive with disease, and 5 dead. Our findings roughly corresponded with those in previously reported cases. Colorectal carcinoma with sarcomatoid components is rare and aggressive, with a poor prognosis for many patients. We suggest that spindled cells, anaplasia, heterologous elements, and/or a component with definable sarcomatous lineage be used to distinguish colorectal carcinoma with sarcomatoid components from undifferentiated carcinoma.

Fine-needle aspiration biopsy diagnosis of histiocyte-rich rhabdomyoblastic tumor (inflammatory leiomyosarcoma): A case report.

Histiocyte-rich rhabdomyoblastic tumor (HRRMT) is an exceedingly rare soft tissue tumor of primitive myogenic differentiation. We report herein a case involving the soft tissue in the left lateral peri-scapular region in a 68-year-old female with a 2-month history of a non-painful soft tissue mass. Ultrasound revealed a solid, ovoid subcutaneous mass lesion that lacked significant internal vascularity. Percutaneous fine-needle aspiration (FNA) biopsy with concomitant core needle biopsy was performed, and a diagnosis of HRRMT was rendered. Cytologic smears were hypercellular, composed of a mixture of foamy histiocytes and a variably cohesive population of epithelioid and plasmacytoid to vaguely spindled cells in cohesive clusters and singly dispersed. Histologic material showed sheets of epithelioid and plasmacytoid to spindled cells with admixed foamy histiocytes with distended, vacuolated cytoplasm. To our knowledge, this is the first reported example of HRRMT evaluated by FNA biopsy.

Revisiting the cytologic features of autoimmune pancreatitis: An institutional experience.

BACKGROUND: Autoimmune pancreatitis (AIP) is a known mimicker of pancreatic ductal adenocarcinoma both clinically and radiologically. In this study, the authors present their institutional experience in diagnosing AIP on cytology and correlate results with the histologic findings. METHODS: A 14-year computerized search for patients who had histologically confirmed AIP with concurrent or prior cytology was performed. Clinical data, cytology findings, and surgical pathology results were reviewed for analysis. RESULTS: Eighteen patients were identified. The patients showed a male predominance, with a mean age of 59 years. Jaundice, weight loss, and abdominal pain were the most common clinical presentation. Five of 12 patients who were tested for serum immunoglobulin G4 had elevated levels. Cytologic findings of 16 cases that were available for review showed markedly inflamed fibrous stroma (54%) and cytologic atypia (50%). The final cytologic diagnoses were suspicious for adenocarcinoma (n = 1), atypical (n = 8), and benign/negative (n = 9). The corresponding surgical pathology diagnoses were classified as type 1 (n = 10), type 2 (n = 6), and AIP, not otherwise specified (n = 2). All type 2 AIP cases had at least atypical cytologic diagnoses, with one called suspicious for adenocarcinoma and another called adenocarcinoma at the time of rapid on-site evaluation. In contrast, eight of 10 type 1 AIP cases were negative/benign, and two of 10 were atypical. In these two atypical cases, the possibility of AIP was raised because of the presence of inflamed stroma. CONCLUSION: AIP is a pitfall in cytology because moderate-to-marked atypia can be present, especially in type 2 AIP. Because atypia can be severe, the presence of cellular fibrous stroma with lymphocytic stromal infiltrates and the integration of serum immunoglobulin G4 levels could be helpful in avoiding diagnostic overcall in AIP.

Fine needle aspiration biopsy of epithelioid-mesenchymal neoplasm with PTCH1-GLI1 fusion: A case report.

Mesenchymal tumors harboring GLI1 gene fusions are a rare new entity that typically occur in the head and neck region of young to middle aged adults, with a particular predilection for the tongue. We report herein a case of epithelioid mesenchymal tumor with PTCH1-GLI1 gene fusion of the right submental region in an 82-year-old male never smoker. Ultrasound-guided fine needle aspiration (FNA) with concomitant core needle biopsy was performed. Cytology smears revealed a hypercellular, monotonous aspirate comprised of epithelioid to plasmacytoid cells with round regular nuclei and moderate amounts of cytoplasm. There were admixed granulomata. The patient underwent surgical resection with limited neck dissection and subsequent pathologic examination with performed next generation sequencing confirmed the presence of epithelioid mesenchymal tumor with PTCH1-GLI1 gene fusion. To our knowledge, this is the first reported example of a mesenchymal tumor harboring GLI1 gene fusion initially evaluated by FNA.

Spindle cell neoplasms of the upper gastrointestinal tract, hepatobiliary tract, and pancreas by fine needle aspiration: A single institutional experience of 15 years with follow-up data.

BACKGROUND: The diagnosis of spindle cell neoplasms (SCN) of the upper gastrointestinal (GI) tract, hepatobiliary tract, and pancreas detected by fine needle aspiration (FNA) is challenging. We describe a single-center experience of these samples with follow-up data and characterization of the morphologic findings. METHODS: We retrospectively reviewed pathology records for all FNAs diagnostic for or suggestive of SCN on esophagus, stomach, small bowel, liver, and pancreas in a 15 year period. All cases with at least 6 month follow-up were included. Surgical material (biopsy or resection) was the diagnostic gold standard. All FNAs with subsequent surgical specimens were reviewed and assessed for cellularity, architectural features, and nuclear features. RESULTS: In 15 years, 5101 FNAs of the upper GI tract, hepatobiliary tract, and pancreas were performed. SCN was diagnosed in 98 (2%) patients. Seventy-two patients had definitive pathologic diagnoses: 68 were neoplastic and four were non-neoplastic. Cytomorphologic review in relationship to final diagnosis revealed three statistically significant features: low cellularity favors a benign process (P = .00544), epithelioid nuclear morphology favors malignancy (P = .00278), and identification of perinuclear vacuoles favors a diagnosis of GIST over non-GIST SCN (P = .04236). CONCLUSIONS: Among cases with follow-up, final pathologic diagnoses were SCN in 94% of cases diagnosed as SCN on FNA of upper GI, hepatobiliary tract, and pancreas. Although some cytomorphologic criteria are more suggestive of malignancy, arriving at a specific diagnosis relies on collaboration of clinical, radiologic, cytomorphologic, and immunohistochemical data.

INSM1 Is a Highly Specific Marker of Neuroendocrine Differentiation in Primary Neoplasms of the Gastrointestinal Tract, Appendix, and Pancreas.

OBJECTIVES: INSM1 has been described as a sensitive and specific neuroendocrine marker. This study aims to compare INSM1 with traditional neuroendocrine markers in gastrointestinal neuroendocrine neoplasms. METHODS: Retrospective review (2008-2018) was used to retrieve paraffin-embedded tissue from 110 gastrointestinal neuroendocrine neoplasms and controls that was subsequently stained with INSM1, synaptophysin, chromogranin, CD56, and Ki-67. RESULTS: INSM1 was positive in 16 of 17 (94.1%) gastric, 17 of 18 (94.4%) pancreatic, 13 of 18 (72.2%) small bowel, 17 of 21 (81.0%) colonic, and 26 of 36 (72.2%) appendiceal tumors. INSM1 was positive in 58 of 70 (82.9%) well-differentiated neuroendocrine tumors, 17 of 20 (85.0%) poorly differentiated neuroendocrine carcinomas, 8 of 11 (72.7%) low-grade goblet cell adenocarcinomas (grade 1), and 6 of 9 (66.7%) high-grade goblet cell adenocarcinomas (grade 2/3). INSM1 sensitivity for neuroendocrine neoplasms (80.9%) was less than that of synaptophysin (99.1%), chromogranin (88%), and CD56 (95.3%); specificity was higher (95.7% vs 86.0%, 87.3%, and 86.0%, respectively). CONCLUSIONS: INSM1 is a useful marker of neuroendocrine differentiation in gastrointestinal neuroendocrine and mixed neuroendocrine neoplasms. Compared with traditional neuroendocrine markers, INSM1 is less sensitive but more specific.

Primary Intraosseous Synovial Sarcoma with Molecular Confirmation: Expanding and Clarifying the Spectrum of This Rare Neoplasm.

Synovial sarcoma is a well-known malignant tumor usually originating within deep soft tissues of the lower extremities of adolescents and young adults. Rare radiologically confirmed examples of primary bone synovial sarcoma have been documented, generally in isolated case reports. Herein, we report two cases of primary intraosseous synovial sarcoma, with molecular confirmation, involving the left humerus of a 45-year-old female and the right fourth metatarsal bone in a 36-year-old male. Additionally, we clarify the spectrum of primary intraosseous synovial sarcoma by separately analyzing reported cases with radiographic confirmation of bone origin and molecular support for the diagnosis. There are clinicopathologic differences between those tumors with documented molecular confirmation and those lacking such confirmation, specifically regarding their anatomic distribution (p < 0.0001). Regarding the radiology of our two cases, the humeral lesion appeared almost entirely intramedullary without soft tissue extension; the midfoot lesion demonstrated a destructive, metatarsal-centered bone lesion, initially thought clinically to represent primary bone osteosarcoma. The diagnoses of monophasic synovial sarcoma were rendered via core needle biopsies, with molecular FISH confirmation of SYT gene rearrangement. Clinical follow-up data was only available for the female patient with the primary humeral lesion, who underwent surgical resection, with no local recurrence or distant metastasis at 7 months postsurgery. To our knowledge, these are the first reported examples of molecularly confirmed, primary intraosseous synovial sarcomas of the humerus and metatarsal bones. Primary intraosseous synovial sarcomas with molecular confirmation differ clinically from those lacking it; however, the demographic features and metastatic potential appear similar to primary soft tissue synovial sarcoma.

Histologic Lesions of Porto-Sinusoidal Vascular Disease Following Phlebotomy in Hemochromatosis.

BACKGROUND: Phlebotomy induces regression of liver fibrosis in genetic hemochromatosis. We assessed the histologic changes in pre-phlebotomy and post-phlebotomy liver biopsies from patients with HFE mutation as a model to study regression of fibrosis. We aimed to show that phlebotomy-induced histologic lesions overlap with porto-sinusoidal vascular disease (PSVD, also known as idiopathic non-cirrhotic portal hypertension), histologically. METHODS: A total of 51 biopsies (22 pre-phlebotomy and 29 post-phlebotomy) were reviewed, and three variables were studied: iron index indicative of the amount of accumulated iron (range 0 to 18), the combined score of vascular changes reflecting the presence of histological lesions that are described in PSVD (range 0 to 9) and the high-grade shunt vessel by calculating the proportion of portal tracts with shunt vessels, with a cutoff of 50%. Two-tailed Student's t-test and Fisher's exact test were performed to compare the means of two variables and frequencies of the histologic lesions in two groups, respectively. A P-value < 0.05 was considered statistically significant. RESULTS: The iron index was higher in the pre-phlebotomy compared to post-phlebotomy group (P = 0.01). Compared to the pre-phlebotomy group, the combined score was higher in the post-phlebotomy group when the cases of advanced fibrosis were excluded (P = 0.023) and remained higher when patients with risk factors for PSVD were further excluded (P = 0.034). The high-grade shunt vessel tended to be more common in the post-phlebotomy group when advanced fibrosis was excluded; however, the statistical significance was marginal (P = 0.056). CONCLUSIONS: Phlebotomy reduces hepatic iron load and induces histologic lesions of PSVD in patients with HFE mutation. Our data support a postulation that some of the histologic lesions of PSVD represent vascular remodeling following a regression of fibrosis and may not be reflective of risk factors or etiopathogenesis of PSVD. Regressed fibrosis and PSVD may not be reliably distinguished in a limited sample, therefore warranting cautious interpretation in the right clinical context.

Primary tumor types and origins in positive abdominopelvic washing cytology, a single institution experience.

INTRODUCTION: Abdominopelvic washing cytology is a common specimen evaluated for ovarian, fallopian tubal, and peritoneal cancer staging or other nongynecologic malignancies presented as metastases. We reviewed our experience in diagnosing abdominopelvic washing specimens and assessing the primary tumor types and origins of the positive abdominopelvic washings. MATERIALS AND METHODS: A pathology archive database search was performed for abdominopelvic washing specimens from 2007 to 2018. The corresponding cytologic diagnoses, results of ancillary studies, clinical histories, and surgical follow-up were reviewed. The primary sites were determined based on the synoptic reports, when available. RESULTS: A total of 5.8% (350 of 6023) of cases were positive for malignancy or neoplasm. Additionally, 1.3% (78 of 6023) were diagnosed as atypical cells. Of the 350 positive cases, 93.4% were müllerian tumors. The frequency of primary sites for müllerian tumors in descending order were: ovary, uterus, fallopian tube, peritoneum, and uncertain müllerian sites. The common ovarian tumors identified in pelvic washing in descending order were: high-grade serous carcinoma, serous borderline tumor, clear cell carcinoma, low-grade serous carcinoma, and endometrioid carcinoma. Gastrointestinal, breast, bladder, and lymphoma primaries were the 23 nongynecologic tumors identified in pelvic washings. CONCLUSIONS: Positive findings in abdominopelvic washing cytology is rare. The majority of the positive cases were from müllerian origins, with ovary and uterus as the most common sites. Endometrial adenocarcinoma, endometrioid type and ovarian high-grade serous carcinoma were the most common tumor types. Knowing prior history of malignancy, morphologic comparison with concurrent surgical cases, and performing ancillary studies are keys to improve diagnostic accuracy of abdominopelvic washings.

The usefulness of lymphoid enhancer-binding factor 1 and androgen receptor in diagnosing solid pseudopapillary neoplasm of the pancreas on cytopathology.

BACKGROUND: Solid pseudopapillary neoplasm (SPN) is an uncommon tumor that is challenging to diagnose on cytology due to morphologic overlap with other pancreatic neoplasms. Recently, putative diagnostic markers for SPN have been reported in the surgical pathology literature, with nuclear positivity for lymphoid enhancer-binding factor 1 (LEF1) and androgen receptor (AR) identified in >90% and >80% of cases, respectively. In the current study, the authors sought to evaluate the sensitivity and specificity of LEF1 and AR on SPN cytology specimens and available corresponding surgical resection specimens. METHODS: Immunohistochemistry was performed using monoclonal antibodies against LEF1 and AR on 19 SPN cytology cases and 15 corresponding follow-up surgical resection specimens from 2 institutions. To evaluate specificity, the authors stained 23 non-SPN tumors diagnosed on cytology with corresponding surgical specimens (4 acinar cell carcinomas, 9 pancreatic neuroendocrine tumors, and 10 ductal adenocarcinomas). Positivity for LEF1 and AR was defined as any nuclear staining within neoplastic nuclei. RESULTS: LEF1 was found to be positive in 18 of 19 cytology cases (94.7%) and 15 of 15 corresponding surgical resection specimens (100%). AR was positive in 4 of 16 cytology cases (25.0%) and 4 of 15 corresponding surgical resection specimens (26.7%). Among non-SPN tumors, LEF1 demonstrated a specificity of 87% whereas the specificity for AR was 100%. CONCLUSIONS: LEF1 for SPN on cytology material was found to demonstrate a sensitivity of 94.7% and a specificity of 87%. Although AR was found to have a specificity of 100%, its sensitivity was lower (25%). LEF1 could be a valuable immunostain on cytology cell block material for the diagnosis of SPN. However, the same may not hold true for AR.

Molecular testing in metastatic colorectal adenocarcinoma cytology cell pellets.

BACKGROUND: Mutational status for KRAS, NRAS, and BRAF genes should be performed on all colorectal carcinoma (CRC) specimens in order to guide targeted therapy selection for metastatic disease. Mutations are typically assessed via polymerase chain reaction and/or next generation sequencing (NGS) on formalin-fixed paraffin-embedded tissues. With minimally invasive diagnostic methodologies, the cytology cell pellet obtained by fine-needle aspiration (FNA) can serve as an alternative source of tumor deoxyribonucleic acid. METHODS: An electronic record review of the cytopathology files (CoPathPlus, Cerner Corp., North Kansas City, Missouri) from September 1, 2015 through December 31, 2018 was conducted. All cytology specimens obtained via FNA and diagnosed as metastatic CRC on which NGS was performed were included. NGS for KRAS, NRAS, and BRAF mutations using the AmpliSeq Cancer Hotspot Panel v2.0 kit (Thermo Fisher Scientific, Waltham, Massachusetts) was performed on cytology cell pellets. RESULTS: Forty-eight cases were identified. Forty-six of 48 specimens (96%) were adequate for molecular testing. Of those adequate specimens, proportion of malignant cells in the sample ranged from 5% to 95% (mean 46%). Twenty-seven of 48 cases (56%) were positive for clinically relevant mutations. Twenty-four of 27 cases (89%) were positive for KRAS mutations, with exon 2 most frequently involved (22/24 cases, 92%). Two of 27 cases (7%) were positive for NRAS mutations and one case (1/27, 4%) was positive for a BRAF mutation involving codon 594. CONCLUSION: Mutational analysis performed on cytology cell pellets serves as a useful means of gathering clinically actionable information on tumor mutation status in metastatic CRC.

Fine-needle aspiration of the liver: a 10-year single institution retrospective review.

Fine-needle aspiration (FNA) of liver masses is a minimally invasive means of evaluation, with diagnostic accuracy over 85%. Given that most of the recent literature on sampling hepatic tumors was published by radiologists and gastroenterologists, we herein conduct a 10-year retrospective review of a single institution's cytopathology experience with the diagnosis of liver lesions. Electronic record review of the cytopathology files (CoPathPlus; Cerner Corp) was conducted for the 10-year interval January 2007 through December 2016. All cytology specimens designated as "liver" and "FNA" were included. Associated concurrent and subsequent surgical pathology and cytopathology cases were identified. All FNA cases were organized into four diagnostic categories: positive for malignancy, atypical, negative for malignancy, and non-diagnostic. There were 713 hepatic FNAs that were categorized as follows: positive for malignancy 467 (65.5%), atypical 49 (6.9%), negative 171 (24.0%) and non-diagnostic 26 (3.6%). Metastatic tumors (95.7%) were more common that primary (4.3%). The top two metastatic primary sites were pancreas (30.1%) and colon (12.7%). A total of 166 (23.2%) cases had concurrent core needle biopsies (CNB). 111 (66.9%) were concordant with the FNA diagnosis. Of the 55 discordant cases, 43 (25.9%) had diagnostic material only on CNB and 12 (7.2%) had diagnostic material only on FNA. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 93.4%, 96.7%, 98.2%, 84.3%, and 89.3% respectively. Irrespective of endoscopic versus percutaneous approach, hepatic FNA is a sensitive and specific means of identifying metastatic and primary malignancies of the liver.

Metastatic SMARCB1 (INI-1)-Deficient Sinonasal Carcinoma Diagnosed by Endobronchial Ultrasound-Guided Fine-Needle Aspiration (EBUS-FNA): A Potential Diagnostic Pitfall and Review of the Literature.

SMARCB1 (INI-1)-deficient sinonasal carcinoma is a rare entity within the subgroup of poorly differentiated sinonasal tract carcinomas. As there are only two papers describing the cytologic features of this entity, herein we describe the unique cytomorphologic features of a pulmonary metastasis of this tumor and include the differential diagnosis based on tumor location. The patient was a 53-year-old male who initially presented with sinus congestion and vision changes including left-eye proptosis and diplopia. The initial biopsy of the ethmoid-centered sinonasal mass was non-keratinizing squamous cell carcinoma based on strong immunoreactivity with p40 and absence of immunoreactivity for chromogranin, synaptophysin, p16, and EBER. However, the final diagnosis of the surgical resection was amended to SMARCB1 (INI-1)-deficient sinonasal carcinoma after additional immunohistochemical stains were performed. Post-primary resection, follow-up computed tomography imaging revealed significant interval progression of a solitary, initially indeterminate 1-cm lung nodule in the left upper lobe. Endobronchial ultrasound-guided fine-needle aspiration with concomitant core-needle biopsy was performed. Rapid on site evaluation of cytologic smears revealed a hypercellular specimen consisting of sheets of epithelioid cells with very scant to absent cytoplasm, ill-defined cell borders, enlarged fragile nuclei, and areas of nuclear molding. Mitotic figures were present. Other areas showed tumor cells with spindled to elongated nuclei and scant to ill-defined wispy cytoplasm. Both cytology cell block and core-needle biopsy histopathologic material showed the tumor cells to be negative for INI-1 nuclear staining as well as CK5/6, CAM5.2, p40, p63, CK7, AE1/3, and TTF-1. SMARCB1 (INI-1)-deficient sinonasal carcinoma can have a spectrum of morphologies and may mimic "small-round-blue-cell" and spindle-cell tumors on cytology preparations. Given the pulmonary location of the aspirate, familiarity with the cytomorphologic spectrum of SMARCB1 (INI-1)-deficient sinonasal carcinoma, inclusion of this entity within the differential diagnosis, and performance of immunohistochemistry will aid in arriving at the correct diagnosis.

Concordance of breast fine needle aspiration cytology interpretation with subsequent surgical pathology: An 18-year review from a single sub-Saharan African institution.

INTRODUCTION: There are many merits to fine needle aspiration cytology (FNAC) in evaluation of palpable breast lesions. We set out to determine the concordance of breast FNAC interpretation with subsequent surgical pathology in the resource-limited healthcare setting of rural Kenya. METHODS: African Inland Church Kijabe Hospital electronic pathology files were retrospectively reviewed from 1/1999-9/2017. All breast FNAC cases and subsequent surgical pathology specimens were identified. FNAC interpretations were categorised according to the International Academy of Cytology Yokohama codes: insufficient; benign; atypical favour benign; suspicious favour malignant; and malignant. Surgical pathology results were categorised as benign or malignant. RESULTS: In total, 695 breast FNACs were identified. A total of 219 (31.5%) had subsequent surgical pathology. Average patient age was 39 years (range 13-88); 95% were female. Nearly all (98%) lesions were palpable. FNAC interpretive categorisation was as follows: 20 (9%) insufficient, 103 (47%) benign, 16 (7%) atypical, 24 (11%) suspicious and 56 (26%) malignant. On histopathology, there were 141 (64%) benign cases and 78 (36%) malignancies (Table 1). The sensitivity of FNAC for detecting malignancy was 85%; specificity was 75%. Positive and negative predictive values were 69% and 88%. Diagnostic concordance between FNAC and histopathology was 79%. For definitively diagnostic FNAC categories, diagnostic concordance was 89%. On histopathology, malignant diagnoses were given in 0 insufficient, 12 (12%) benign, 4 (25%) atypical, 11 (46%) suspicious and 51 (91%) malignant cases. There were five false-positive cytopathology interpretations and 12 false-negatives. CONCLUSIONS: FNAC remains a valuable tool in evaluation of palpable breast lesions in resource-limited healthcare settings.

Hyalinized Neurofibromas: Not Just Rare Variants in Skin of the Female Breast.

Although classical neurofibromas are commonly encountered skin lesions, histologic variants are infrequent. We report a greater than 15-year retrospective review of a single institution's experience with the histopathologic diagnosis of neurofibroma of the female breast with a focus on the hyalinized variant. An electronic histopathology record review (CoPathPlus; Cerner Corp, North Kansas City, MO) was conducted from January 1, 2000, to October 16, 2015, for all "neurofibroma" diagnoses rendered in "females" at the anatomical site "breast". All cases were microscopically revisited and subclassified into 1 of 10 histopathologic categories. Immunohistochemistry (IHC) for S100, tryptase, and CD117 were performed on 19 hyalinized and 19 age-matched classical neurofibromas. During the study period, 62,021 breast specimens were reviewed at our institution. Of these, 86 (0.14%) were diagnosed as neurofibromas. Subclassification was as follows: 50 classical (58%), 19 hyalinized (22%), 6 diffuse (7%), 5 cellular (6%), 3 myxoid (4%), 2 epithelioid (2%), and 1 plexiform (1%). All hyalinized and age-matched classical neurofibromas were S100 positive. The mean number of IHC-positive mast cells per high-power field (hpf) was 34.5 by tryptase and 26.8 by CD117 for the hyalinized subset and 22.5 by tryptase and 19.3 by CD117 for the classical cohort. Published literature reports a 2.6% incidence of hyalinized neurofibromas at nonspecial cutaneous sites. Our series details a 22% incidence in the breast. Regarding pathophysiology, there is a statistically significant increase in the average number of IHC-positive mast cells per hpf in hyalinized variants when compared with classical neurofibromas of the breast both by tryptase (P = 0.00157) and CD117 (P = 0.00901).

Atypical "Sclerosing" Osteoblastic Neoplasm: A Tumor of Intermediate Biological Potential Between Usual Osteoblastoma and Conventional Osteosarcoma.

The existence of "aggressive" osteoblastoma (OB) or malignant transformation of OB is controversial. Over a few decades, we have encountered a group of "borderline" sclerosing osteoblastic lesions that are difficult to classify, tending toward local recurrence, especially following curettage. A search of the consultative and institutional files from 3 co-authors for atypical OB, malignant transformation of OB, well-differentiated osteosarcoma (OS), and OB-like OS diagnoses revealed 8 similar cases. There were 6 males and 2 females, ages 11 to 55 years (mean, 26 y). Three arose in metatarsals, 2 in the fibula, and 1 each in the humerus, tibia, and femur. Radiologically, most were expansile, lytic to sclerotic, with circumscribed and at least partially sclerotic borders. Pathologically, all displayed a predominant, sclerosing sheet-like neoplastic bone growth pattern, associated with minor components of conventional OB. No solid sheets of osteoblasts or permeation of surrounding bone were identified. Six cases were reviewed by >1 expert orthopedic pathologist, often with divergent opinions. Four were initially diagnosed as OB, 2 as low-grade OS, 1 as high-grade OS, and 1 as atypical sclerosing osteoblastic neoplasm. Clinical follow-up for 7 patients ranged from 12 to 138 months (mean, 71 mo). Four underwent curettage only; 2, curettage and en bloc resection with negative margins; 1, en bloc intralesional resection, and 1 amputation. 5 locally recurred, with 3 "reclassified" as OSs. One local recurrence was considered dedifferentiation. Whether these tumors represent low-grade OSs or aggressive forms of OB remains unclear. We recommend classifying these neoplasms as "atypical sclerosing osteoblastic neoplasm" and performing complete resection with negative margins.

Does Strong and Diffuse PAX-8 Positivity Occur in Primary Lung Carcinoma? An Immunohistochemical Study of 418 Cases and Review of the Literature.

Although rare cases of PAX-8-positive primary lung carcinoma have been reported, details of staining distribution and intensity in such cases are limited. The aim of this study was to determine whether strong and diffuse PAX-8 staining can occur in primary lung carcinoma. Immunohistochemical staining for PAX-8 (Rabbit polyclonal, 10336-1-AP; Proteintech) was performed on whole-tissue sections from 418 resected primary lung carcinomas. PAX-8 was positive in 5/418 (1.2%) cases, all of which were large cell neuroendocrine carcinomas. Staining was weak to moderate in all 5 cases, and was seen in 5% to 30% of tumor cells. All other primary lung carcinomas (413/418) were negative for PAX-8. This study-the largest series of PAX-8-stained whole-tissue sections of primary lung carcinoma to date-shows that strong and diffuse staining for PAX-8 does not occur in primary lung carcinoma of any type. This staining pattern in a carcinoma in a lung specimen provides strong evidence of nonpulmonary origin.

Sensitivity of Cerebrospinal Fluid Cytology for the Diagnosis of Cryptococcal Infections: A 21-Year Single-Institution Retrospective Review.

Objectives: Cryptococcal meningoencephalitis is the most common fungal infection of the central nervous system diagnosed by cerebrospinal fluid cytology (CSF) studies. Existing literature suggests that routine CSF cytomorphologic evaluations are exquisitely specific; however, less is known about their sensitivity. Methods: An electronic record review of the cytopathology and microbiology files was conducted for the 21-year interval from January 1, 1995, through December 31, 2015. Results: In 21 years, 12,584 CSF samples were processed in the laboratory. Of these, 24 (0.2%) were reported positive for cryptococcal organisms by light microscopy, and 129 CSF fungal cultures were positive for Cryptococcus species. All cotested specimens with positive cytology results were positive on culture (15 specimens, 100% specificity). Twenty-four samples with positive culture results were negative by CSF cytology (sensitivity 39%). Conclusions: When culture is used as a gold standard, CSF cytology is 100% specific and 39% sensitive, with a positive predictive value of 100% and a negative predictive value of 99.8%.