Case of the Month

Each Case of the Month is created for pathologists to share interesting cases, to collaborate on research and for educational purposes.

For each case of the month, you can submit your diagnosis. Feedback will be given the following month — once the case has moved to our archives.

If you would like to contribute a case to be featured here as a Case of the Month, please submit it.

Current Pathology Case

Return each month to see our new case study, as well as to find out if your diagnosis was correct! 


  • 74-Year-Old Man with h/o Central Spinal Stenosis.
    • Final Diagnosis – Anaplastic large cell lymphoma, ALK-negative. 
  • 14-Year-Old Female Presented for Evaluation of Three Days of Periumbilical Pain.
    • Final Diagnosis – Chordoma.
  • 72-Year-Old Patient with Pancytopenia, Gradually Worsening, with Concern for Possible Leukemia.
    • Final Diagnosis – Bone marrow, biopsy and aspirate – blastic plasmacytoid dentric cell neoplasm.
  • A Male Infant Born at 36-Weeks Gestational Age Experienced Cardiac Dysfunction.
    • Final Diagnosis – Rhabdomyomas.
  • A 41-Year-Old Man who Presents for Evaluation of Right Arm Cyst.
    • Final Diagnosis – Nodular histiocytic proliferation, compatible with Rosai-Dorfman disease.
  • An 84-Year-Old Woman was Referred for Biopsy of a Two cm Left Upper Lobe Lung nodule.
    • Final Diagnosis – Metastatic spindle cell/ sarcomatoid/ metplastic carcinoma of breast origin (with minor squamous component).
  • A 10-Year-Old Female was Reevaluated after Direct Injury to the Right Eye:
    • Final Diagnosis – Extranodal mucosa-associated B-cell lymphoma (MZL).
  • A 65-Year-Old Man with Small Bowel Perforation and Sepsis:
    • Final Diagnosis – Diffuse large B cell lymphoma with plasmacytic differentiation.
  • 73-Year-Old Man with Intrathoracic and Intrabdominal Lymphadenopathy and Liver Lesions:
    • Final Diagnosis – Lymph node, retroperitoneal, core needle biopsy — diffuse large B-cell lymphoma, GCB subtype, with aberrant MYC expression.
  • 75-Year-Old Man with a 1.1 cm Solid Mass in Left 12:00, three cm from Nipple:
    • Final Diagnosis – Bland spindle cell lesion, consisted with myofibroblastoma.
  • 14-Month-Old Male Infant was Evaluated for a Palpable, Ovoid Subcutaneous Lesion:
    • Final Diagnosis – Deep granuloma consistent with vaccine granuloma.
  • 79-Year-Old Man with h/o MDS/MPN, Treated with Epoetin, Now Concern for Conversion to AML:
    • Final Diagnosis – Bone marrow, site unspecified, aspirate, clot section and biopsy.
  • Six-Year-Old Male Child Presented for Workup of Pain upon Defecation:
    • Final Diagnosis – Hamartomatous rectal polyps.
  • 72-Year-Old Male with History of Multiple Cardiopulmonary Diseases:
    • Final Diagnosis – Tumor, left lateral bladder wall, TURBT.
  • 7-Year-Old Female Presents with Slowly Progressive Dysphagia, Headache, Ataxia and Dysarthria:
    • Final Diagnosis – ALK-positive histiocytosis.
  • 73-Year-Old Male Presents with Red/Purple Blotches:
    • Final Diagnosis – Skin, left upper arm, punch biopsy — cutaneous involvement by lymphoplasmacytic; and skin, left dorsal hand, shave biopsy — basal cell carcinoma, nodular type, transected.
  • 8-Year-Old Female Presented for Biopsy of a Focal Cluster of Violaceous Papules:
    • Final Diagnosis – Acral pseudolymphomatous angiokeratoma.
  • 70-Year-Old Man with Weight Loss, Random Biopsies Taken at Colonoscopy:
    • Final Diagnosis – Involved by systemic mastocytosis.
  • 78-Year-Old Caucasian Male with History of Multiple Non-Melanocytic Skin Cancers:
    • Final Diagnosis – Skin, left eyebrow, excision — basosquamous carcinoma involving the deep marginskin and perineurial invasion identified.
  • 74-Year-Old Veteran with Past Exposure to Chemicals:
    • Final Diagnosis – Moderately hypercellular marrow with multifocal atypical mast cell proliferation.
  • 68-Year-Old Male with PMH:
    • Final Diagnosis – Skin, excisional biopsies: squamoid eccrine duct carcinoma and foci suspicious for lymphovascular invasion identified.
  • 72-Year-Old Male with HGT1 Bladder Ca s/p TURBT + intravesical MMC:
    • Final Diagnosis – Mass, testicle and spermatic cord, resection.
  • A 72-Year-Old Female with a Three-Month History of Worsening Headaches:
    • Final Diagnosis – Meningioma arising from the basal skull.
  • A 39-Year-Old Male Found Unresponsive at Home:
    • Final Diagnosis – Benign colloid cyst.
  • A 31-Year-Old Man with a Painless Lump:
    • Final Diagnosis – Malignant germ cell tumors, seminoma and embryonal. The seminoma was 3.8 cm in greatest dimension, and the embryonal carcinoma was 1.5 cm in greatest dimension.
  • A 62-Year-Old Man with a Neck Mass:
    • Final Diagnosis  Dendritic cell neoplasm, favoring interdigitating dendritic cell sarcoma.