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Case Presentation – August 2025

Cervical Changes in Allogeneic Hematopoietic Stem Cell Transplantation Patients

Written by: Hannah Maycon, student, Cleveland Clinic Cytology Program, Cleveland, Ohio

Patient Age: 42-year-old female

Specimen Type: Cervical Pap test: Pap stain, ThinPrep® Pap Test

Patient History: This patient was diagnosed with acute myeloid leukemia. She received combination chemotherapy, including busulfan and cyclophosphamide, prior to an allogeneic hematopoietic stem cell transplant (allo-HSCT). A routine Pap test was performed 172 days post-allo-HSCT.  The patient had no history of abnormal paps.

Cytologic Diagnosis: Atypical Squamous Cells of Undetermined Significance (ASCUS), likely related to chemotherapy-effect.  The associated high-risk HPV test was negative.

Biopsy / Pathologic Diagnosis: No further biopsies were taken.

Case provided by: Cleveland Clinic, Cleveland, Ohio

Cervical Changes in Allogeneic Hematopoietic Stem Cell Transplantation Patients

 Etiology:

Therapeutic treatments, including radiation and chemotherapy, are known to interfere with benign cell morphology. For instance, busulfan has been known to affect the epithelium of the lung, liver, adrenal gland, sinonasal tract, pancreas, breast, and cervix1. This drug is an alkylating agent that inhibits cancer cell proliferation by manipulating the molecular integrity of the cells’ DNA and histone proteins2. Patients who have received busulfan as part of a conditioning regimen for allogeneic hematopoietic stem cell transplantations (allo-HSCT) are about 13 times more likely to develop cervical cancer3,4. Therefore, the American Society for Blood and Marrow Transplantation recommends these immunocompromised patients receive regular pap tests every one to three years4, 5. The cytological diagnoses are often atypical, resembling a precancerous lesion or a malignancy. It has been suggested that the time elapsed between conditioning therapy with busulfan and Pap tests is an important factor that may influence the diagnoses. Although there are few studies examining this phenomenon, epithelial atypia is typically observed within a year of busulfan exposure. Furthermore, in almost all cases, this atypia regresses, and is not seen in follow-up Pap tests1, 3, 6, 7. Therefore, it is recommended that the clinical history of treatments and HPV status be considered before making a diagnosis in patients known to have a bone marrow transplant. Additionally, it may be best to postpone Pap tests directly following conditioning therapy with busulfan, to avoid an initial abnormal specimen and unnecessary procedures for patients3, 6.

Clinical Features: 

The consistent clinical feature in these patients is a history of blood cancer, including acute myeloid leukemia, acute lymphoblastic leukemia, non-Hodgkin lymphoma, multiple myeloma, Hodgkin lymphoma, myelodysplasia, thalassemia, and aplastic anemia6, 7. Approximately half of these patients will experience a post-transplant disease known as Graft-versus-Host-Disease, in which the donor’s cells attack the recipient’s tissue8. Additionally, there is evidence that those diagnosed with Graft-versus-Host Disease are at an increased risk of developing a precancerous lesion related to HPV3, 6. Most of the allo-HSCT patients have no history of abnormal Pap tests and are HPV negative. However, there are few studies that have examined cervical changes in these patients, and several of them do not have information on HPV status. Additionally, there are a number of patients who have no previous Pap history before developing cancer1, 3, 4, 6, 7. In rare instances, patients became exposed to HPV, testing positive for Type 16 or other high-risk variants, after their initial Pap test. Precancerous lesions were found on their follow-up Pap test as well as on histology3.

Treatment and Prognosis:

The American Society for Colposcopy and Cervical Pathology outlines the treatment of an atypical Pap test. Treatments vary depending on the patient’s immediate risk of developing CIN3+. This assessment is based on cytological diagnosis, HPV test results, and, if applicable, colposcopy results. The immediate CIN3+ risk must be lower than 4% to avoid colposcopy or expedited treatment. However, if the patient is immunocompromised, the guidelines differ, as these individuals are more likely to contract HPV and possibly develop cervical cancer. If the patient is HPV positive with an ASCUS cytology diagnosis, a colposcopy is recommended for management. Furthermore, if the patient receives an LSIL diagnosis on cytology, a colposcopy is recommended regardless of HPV status9. The patient in this case received an ASCUS diagnosis due to the recent exposure to busulfan and a negative HPV result. There is a favorable prognosis for patients with therapy-induced cervical atypia, as the atypia typically regresses and leads to a NILM diagnosis on subsequent Pap tests, which occurred in our patient as well. However, there are a number of adverse effects associated with busulfan, such as intestinal mucosal damage, alopecia, pancytopenia, anemia, amenorrhea, increased risk of malignancy, hepatic veno-occlusive disease, interstitial pulmonary fibrosis, and seizures2. After the transplant and conditioning therapy which included busulfan, this patient was afflicted with MRSE bacteremia, pancytopenia, GVHD, and vaginal atrophy1, 3, 6, 7.

Cytology:

The most prominent features observed from these cervical specimens are cells with enlarged, hyperchromatic, and irregular nuclei. The nuclei are centrally located and may appear smudgy or opaque with degenerative nuclear inclusions. The cells have dense, squamoid cytoplasm, often with cytoplasmic vacuoles. There are groups of cells, including reparative groups, with streaming nuclei and syncytial groups with high nuclear to cytoplasmic (N/C) ratios. Meanwhile, single cells can be observed with varying amounts of cytoplasm ranging from low to high N/C ratios. An increased number of naked nuclei may be present in clusters throughout the slide. The background may also be filled with debris or fibrinous material1, 3, 6, 7.

Differential Diagnosis:

Therapeutic treatments can make diagnosing cytological specimens difficult, as benign cells can be morphologically affected and resemble malignant cells. Therefore, it is necessary to take the clinical history of the patient into consideration before making such a diagnosis, as this can spare the patient from unnecessary procedures.

The first differential in this case is squamous cell carcinoma. The hyperchromatic, smudgy nuclei resemble the opaque nuclei characteristic of keratinizing squamous cell carcinoma. Additionally, there are cells with lower N/C ratios that resemble tadpole cells, which is another common feature in this carcinoma. The grungy, fibrinous-filled background resembles necrosis or tumor diathesis. Squamous cell carcinomas are highly associated with HPV, especially Type 16, and therefore have high p16 expression. However, the studies on cervical changes after allo-HSCT note that most patients are HPV negative and do not have a previous abnormal Pap test 1, 3, 6, 7. Furthermore, immunohistochemistry was negative for p16 in the patients who were HPV negative with cervical atypia6, 7.

Another differential for this entity is a high grade squamous intraepithelial lesion (HSIL). These precancerous lesions are characterized in cytology by high N/C ratio cells with hyperchromatic nuclei and, coarse chromatin. The cytoplasm is dense with centrally located nuclei. Cells can be seen in syncytial clusters, also known as hyperchromatic crowded groups. Naked nuclei may be present, although a diagnosis of HSIL cannot be made on this criterion alone. Approximately 90% of patients with HSIL are HPV positive; meanwhile, a majority of the patients observed to have therapy-induced cervical atypia are HPV negative. Additionally, upon colposcopy examination and histological review, high grade lesions are not present in patients post allo-HSCT treatment. Lastly, when applicable, immunohistochemistry are negative for p16 and Ki67, which are typically overexpressed in cervical lesions1, 3, 6, 7, 10.

Finally, therapy-induced cervical changes can be mistaken for atrophic changes. An atrophic cervical specimen is recognized by an abundance of parabasal cells, due to the decreased amount of estrogen. The cells are predominantly found in sheets and can mimic hyperchromatic crowded groups seen in cervical specimens affected by treatment. There may also be naked nuclei throughout the slide, as well as a background of cellular debris, which is also an effect of treatment. However, the reactive groups from treatment effect will have anisonucleosis and smudged, hyperchromatic, irregular nuclei. The parabasal nuclei will be uniform, with finely granular chromatin and smooth nuclear membranes. Additionally, the abundance of cytomegaly is not a characteristic of atrophy, but rather reactive changes due to treatment1, 3, 6, 7, 11.

  References:

  1. Saco A, Alòs S, Esteve R, et al. Atypical Cytological Changes Mimicking SIL of the Uterine Cervix in Allogeneic Hematopoietic Stem Cell Transplantation Recipients Treated with Busulfan. Cancer Cytopathology. 2019;127(6):399-406. DOI: 10.1002/cncy.22148
  2. Patel R, Patel P, Tadi P. Busulfan. [Updated 2024 Mar 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555986/
  3. Saco A, Carbonell S, Rakislova N, et al. Human Papillomavirus Infection and Cytological Atypia in Female Allogeneic Hematopoietic Stem Cell Transplantation Recipients. Transplantation. Published online January 23, 2025. doi:10.1097/TP.0000000000005323
  4. Hwang JP, Ahmed S, Ariza-Heredia EJ, et al. Low Rate of Cervical Cancer Screening among Women with Hematologic Malignancies after Stem Cell Transplant. Biol Blood Marrow Transplant. 2018;24(5):1094-1098. doi:10.1016/j.bbmt.2018.01.019
  5. Rizzo JD, Wingard JR, Tichelli A, et al. Recommended screening and preventive practices for long-term survivors after hematopoietic cell transplantation: joint recommendations of the European Group for Blood and Marrow Transplantation, the Center for International Blood and Marrow Transplant Research, and the American Society of Blood and Marrow Transplantation. Biol Blood Marrow Transplant. 2006;12(2):138-151. doi:10.1016/j.bbmt.2005.09.012
  6. Yu SC, Huang HH, Li CC, et al. Cervical Papanicolaou Smears in Hematopoietic Stem Cell Transplant Recipients: High Prevalence of Therapy-Related Atypia during the Acute Phase. Biol Blood and Marrow Transplantation. 2017;23(8):1367-1373. DOI:10.1016/j.bbmt.2017.04.022
  7. Negri G, Hertz M, Deola S, et al. Abnormal Cervical Cytology After Allogeneic Bone Marrow Transplantation. American Journal of Clinical Pathology. 2014;142(2):222-226. DOI: 10.1309/AJCP4SKAUS9TOTJX
  8. Justiz Vaillant AA, Modi P, Mohammadi O. Graft-Versus-Host Disease. [Updated 2024 Jun 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538235/
  9. Perkins RB, Guido RS, Castle PE, et al. 2019 ASCCP Risk-Based Management Consensus Guidelines for Abnormal Cervical Cancer Screening Tests and Cancer Precursors [published correction appears in J Low Genit Tract Dis. 2020 Oct;24(4):427. doi: 10.1097/LGT.0000000000000563.]. J Low Genit Tract Dis. 2020;24(2):102-131. doi:10.1097/LGT.0000000000000525
  10. Squamous intraepithelial lesion (SIL). Cleveland Clinic. February 13, 2025. https://my.clevelandclinic.org/health/diseases/22042-squamous-intraepithelial-lesion-sil. Accessed February 23, 2025.
  11. Hasteh F. Cervix Benign / nonneoplastic epithelial lesions Atrophy. PathologyOutlines.com. https://www.pathologyoutlines.com/topic/cervixcytologyatrophy.html. Accessed February 23, 2025.

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