Case of the Month February by Allan Argueta Morales 

CaseReport:

Rebuilding a Diagnostic Puzzle: Integrating History and Morphology

An 82-year-old male, who was asymptomatic, underwent follow-up for a simple kidney cyst by magnetic resonance imaging (MRI). A tumor on the lower lobule of the left lung was detected. A thoracic computed tomography showed the following findings:

inthelowerlobeoftheleftlung

A full-body positron emission tomography (PET) scan was performed, revealing only the two previously mentioned lesions.

At this point, the patient denied any previous history of malignancy, so the clinician decided to perform an Endobronchial Ultrasound with Bronchoscope-Guided Fine-Needle Aspiration from the hilar adenopathy, under the suspicion that this would be a primary lung tumor. Aspirate smears and a cell block were obtained from the EBUS-B-FNA. Rapid On-Site Evaluation (ROSE) was performed.

Highly cellular smears

Epitheloid cells that are distributed diffusely and form small clusters

Middle and large size cells, with oval to round nuclei and the presence of frequent nucleoli

Eccentric nuclei, abundant cytoplasm, and the presence of some cells with multiple nuclei

Occasional nuclear inclusions

The presence of atypical mitotic figures

A poorly differentiated tumor, suspected of being a primary pulmonary neoplasm, was observed, so, initially, the following immunohistochemical studies were requested:

  • TTF1
  • Napsin A
  • CK7
  • CKAE1/AE3
  • p40

All these markers where negative.

So, if you were thinking it was a poorly differentiated adenocarcinoma, and you see all these negative markers, you might be feeling a bit lost at this point, probably thinking of requesting a SMARCA4 determination.

But sometimes, it’s more important to review the clinical background before going further and requesting new immunohistochemical markers. So, we decided to ask the clinicians for further clinical details, including whether the patient was a smoker. They revealed that the patient had never been exposed to tobacco.

With this new information, we re-evaluated our diagnosis: what if this is not a primary tumor of the lung, but actually a metastasis?

So, we started to look carefully at our cytological features:

Eccentrically placed (plasmacytoid) nuclei

Binucleation

Prominent nucleoli

intranuclear cytoplasmic inclusions

Given these cytological findings, we decided to request two other immunohistochemical markers:

Sox10
HMB45

The final diagnosis was of metastasis of melanoma. The patient was referred to dermatology for a general examination, but only four nevi were identified, with no lesions consistent with melanoma. Although primary pulmonary melanoma is recognized in the 2021 WHO classification of pulmonary tumors, we believe this is most likely a metastasis from skin melanoma that has regressed.

Comment:

The clinical history of a patient is a fundamental aspect of pathological diagnosis. When working with pathological samples, understanding the patient’s medical background, symptoms, and risk factors provides crucial context for interpreting the findings. Without this information, it is easy to misinterpret or overlook certain diagnostic clues. Clinical history helps guide the differential diagnosis and ensures that all possible conditions, including rare or atypical ones, are considered. Therefore, a thorough review of the patient’s history is essential to reach an accurate diagnosis and provide the best possible care.

When working with our pathological samples, morphology should always be our first biomarker, before requesting any unnecessary immunohistochemical studies. Melanoma is the eternal mimic, the tumor that should consistently be considered in our differential diagnosis, as it can exhibit a wide range of nuclear patterns. However, it often presents with distinct features, such as prominent nucleoli, intranuclear cytoplasmic inclusions, binucleation, and may also contain cytoplasmic pigment.

Primary pulmonary melanoma (PPM) is an entity recognized in the 2021 World Health classification of lung tumors, which has been described in multiple publications dating from 1916, and is classified in a group termed “tumors of ectopic origin”, which encompass tumors that are more common presented in other sites, but sometime can arise as primary pulmonary tumors. The actual existence of this entity is doubted, and the most accepted theory to this day attempting explain these tumors is that they are a metastases from a primary cutaneous melanoma with regression, a well-described phenomenon.

Author of the case

Allan Argueta, MD Special thanks to M.D. Lozano M.D., Ph.D. for her support in the developing of this case.

REFERENCES

Nicholson AG, Tsao MS, Beth Beasley M, Borczuk AC, Brambilla E, Cooper WA, et al. The 2021 WHO Classification of Lung Tumors: Impact of Advances Since 2015. J Thorac Oncol [Internet]. 2022 [cited 2023 Jan 20];17(3):362–87. Available from:

https://doi.org/10.1016/j.jtho.2021.11.003

Yang C, Sanchez-Vega F, Chang JC, Chatila WK, Shoushtari AN, Ladanyi M, et al. Lung-only melanoma: UV mutational signature supports origin from occult cutaneous primaries and

argues against the concept of primary pulmonary melanoma HHS Public Access. Mod Pathol [Internet]. 2020 [cited 2023 Jan 20];33(11):2244–55. Available from:

https://doi.org/10.1038/s41379-020-0594-0

Sekine I, Kodama T, Yokose T, Nishiwaki Y, Suzuki K, Goto K, et al. Rare pulmonary tumors – a review of 32 cases. Oncology [Internet]. 1998 [cited 2023 Jan 21];55(5):431–4. Available

from: https://pubmed.ncbi.nlm.nih.gov/9732221/

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A summary of the XIII Molecular Cytopathology Congress

9-10 December, 2024 – Naples, Italy

Dear reader,

In its 13th edition, in December 2024 and under the direction of Dr. Giancarlo Troncone, Head of the Department of Public Health, University of Naples Federico II, The Congress of Molecular Cytopathology was held for the first time in a majestic and imposing venue “Church of Saints Marcellinus and Festo”.

The convent building is the result of the union of two neighboring Basilian monasteries dating back to the early Middle Ages. With a Baroque architectural style, it has no waste and every angle is worthy of admiration. From the facade designed by Di Conforto and D’Apuzzo, at the beginning of the 17th century, passing through the dome of the Di Conforto, concluded in 1645, and the interior with a Latin cross plan, a single nave and six side chapels decorated with polychrome marble and carved wood.

This international event, besides being a product of collaboration between cytopathologists from Europe and the United States, provides the opportunity to share and exchange experiences and to learn from the path that others have already passed.

Cytology molecular techniques and testing have rapidly evolved over the years, not only for predictive or prognostic purposes but also for treatment. Due to this, molecular testing must be included in our routine daily practice in which the convergence of a multidisciplinary team (cytopathologists, clinicians: pneumologists, endocrinologists, oncologists, radiologists, among others, as well as technical personnel and molecular biologists), is also essential to obtain adequate and optimal results.

Small specimens are increasingly used for diagnostic and predictive biomarker testing. There is a wide variability in the sampling modality based not only in the clinical presentation and in the access ‘way to the lesion, but also on the infrastructure, logistic and financial particularities of each laboratory. Being the expertise of the clinicians and the cytotechnologists or cytopathologists to evaluate and judicious monetize the sample in the most effective and efficient way possible, an important factor.

Another particularity of this meeting has been the emphasis on the need to homogenize our nomenclatures and reporting systems. To establish quality criteria in all phases of the process, being the pre-analytical phase the one that has more impact on the results with entirely dedicated sessions to acquisition, handling/processing and storage (collection/ transport’s media and fixation) of samples in order to ensure nucleic acids’ preservation.

I n our daily practice, samples are subject to several uncontrolled, unknown and undocumented factors that may alter their molecular quality and composition and therefore the results. As for today, there are currently no requirements to control or record pre-analytical variables nor international guides to follow.

There is a need to properly evaluate sample processing and develop standardize recommendations for optimizing pre-analytical variables and ancillary testing in order to assure the quality and reliability of the analysis avoiding skew data.

This last congress edition, was mainly focused in two organs, thyroid and lung, it was structured in 9 sessions, distributed in two days, full of information, bibliography, experiences, new educational resources among many other things, providing an opportunity to obtain the necessary tools to improve the outcome for cancer patients worldwide based on a better pathology and molecular diagnosis.

With its very particular microphone, icon of the event, we are looking forward to the next edition later this year.

Cioly Rivero Colmenarez, MD, MIAC.

EFCS Residents and Young Cytopathologists Committee Co-chair.

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Case of the Month

A 79-year-old male presented with a peri-rectal tumour measuring 20×16 mm without any additional clinical data. Endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNA) of the tumour was performed. The sample was stored in the cell medium and cytospins were prepared.

QUESTIONS

  1. Describe what you see.
  2. What does it represent?
  3. What is its significance?
Fig. 1. May-Grunwald-Giemsa stain (MGG), x200
May-Grunwald-Giemsa stain (MGG), x400
Fig. 3.May-Grunwald-Giemsa stain (MGG), x400
Fig. 4. Papanicolaou stain (PAP), x400

Fig. 5. Papanicolaou stain (PAP), x600

Fig. 6. Immunocytochemical reaction (ICC) PAX8, x400

Fig. 7. Immunocytochemical reaction (ICC) GATA3, x400

Fig. 8. Immunocytochemical reaction (ICC) CK5.6, x400

Fig. 9. Immunocytochemical reaction (ICC) CK7, x400

ANSWERS

a)

  • predominantly dissociated cells forming discrete, small, poorly cohesive clusters
  • moderately abundant, dense cytoplasm, focal coarse golden-brown pigment (Papanicolaou stain)
  • oval and round nuclei, pronounced anisonucleosis, nuclear hyperchromasia, nucleoli
  • abundant, thick proteinaceous material, sperms with long tails in the background

b) The cytomorphological picture and positive PAX8, GATA3, CK7, CK5.6 results and negative NKX3.1 and SATB2 immunocytochemical reactions were consistent with the diagnosis of a seminal vesicle.

c) Imaging studies prior to EUS-FNA showed that the most likely diagnosis was a peri-rectal soft tissue tumour. When a neoplastic process is suspected, and the epithelioid cell atypia is so pronounced, the differential diagnosis should include carcinoma, e.g., primary colon cancer, but also carcinoma arising from the surrounding organs, e.g., prostate, bladder, and kidney. The immunocytochemical reactions performed certainly excluded metastases of primary colon cancer and prostate cancer but not kidney or bladder cancer. While the cells were quite atypical, the presence of spermatozoa in the background of the sample, in combination with the coarse-grained golden-brown pigment (lipofuscin) in the cytoplasm were the key to the correct diagnosis.

Comment:

The EUS-FNA diagnosis of seminal vesicle raised the question of whether the sample was diagnostic, so comparison with the results of imaging studies was essential. In our case, after re-evaluation of the imaging studies, it was concluded that the peri-rectal lesion was a seminal vesicle because the imaging studies showed an association with the prostate.

Seminal vesicle sampling is infrequent in contemporary cytopathological practice. It may occur in patients with a history of previous abdominoperineal pelvic surgery or colorectal surgery because the seminal vesicles may be displaced posteriorly after abdominoperineal resection, giving the false appearance of a peri-rectal mass on radiologic imaging. However, our patient had no information about any previous surgeries, but this does not exclude them. The cytomorphology corresponding to the seminal vesicle may be very similar to residual colon adenocarcinoma after neoadjuvant chemoradiotherapy and resection. However, a negative SATB2 immunocytochemistry and a positive CK7 immunocytochemistry in combination with the cytomorphological picture can exclude the possibility of a primary colon adenocarcinoma.

Satturwar S, Monaco SE, Xing J, Brand RE, Pantanowitz L. Bizarre benign cells in peri-rectal endoscopic ultrasound-guided fine-needle aspiration due to seminal vesicle sampling. Diagn cytopathol. 2020;48(6):586-8.

Liaquat S, Idowu MO, Hatfield BS. Seminal vesicle adherent to rectal wall following neoadjuvant chemoradiotherapy: a potential false-positive diagnostic pitfall. Int J Surg Pathol. 2020;28(4):406-9.

Clinical case and pictures provided by:

Damjana Cimerman,

YEFCS co-chair

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