Histopathological Evaluation of Multiple Masses

A Case Series Presentation

Histopathological examination remains the gold standard for definitive diagnosis of tissue lesions. Through microscopic evaluation, pathologists can identify the cellular characteristics

Histopathology is particularly helpful in:

Differentiating benign from malignant tumors,

Identifying the tissue of origin,

Determining tumor grade and invasiveness,

Assessing surgical margins, and

Providing prognostic information that guides clinical decision-making.

PLASMA CELL TUMOR (PLASMACYTOMA)

History

Clinical Presentation

Gross findings

Histopathology

Treatment plan

A 10-year-old cat presented with a firm, solitary, slow-growing dermal nodule on the lateral thoracic wall noticed for several weeks

The mass was well-circumscribed, non-ulcerated, and non-painful. No systemic abnormalities were detected on physical examination or bloodwork.


A solitary, round, firm dermal mass measuring 1.5 cm in diameter. The cut surface was smooth, tan to reddish, and homogenous without areas of necrosis or ulceration

The lesion expanding the dermis, with dermal collagen and adnexa compressed. The neoplasm composed of diffuse round cells infiltration (Fig. 1). Neoplastic cells had variably distinct cell borders and moderate amounts of eosinophilic, granular cytoplasm, and toward the periphery of the neoplasm, few cells had a perinuclear pale area (hof). Nuclei showed nuclear pleomorphism with irregularly round with variability in chromatin pattern, which ranged from finely stippled to dense indistinct nucleolus, moreover, some examined sections showed scattered cells with fragmented nucleus. Mitotic figures were noticed. Within the neoplasm, there was marked anisokaryosis. Bi and multinucleated tumor giant cells were frequently detected (Fig. 2). Some examined sections showed lymphocytic infiltration between muscle bundles.

Conclusion:
Plasma cell tumor (plasmacytoma).

Complete surgical excision was performed. Regular follow-up was advised to monitor for local recurrence or systemic involvement.

.

.

.

.

.

.

.

.

.

GIANT CELL TUMOR OF TENDON SHEATH

When Diagnosis Becomes Uncertain: A Giant Cell Tumor of Tendon Sheath Mimicking Osteosarcoma”

History

Clinical Presentation

Histopathology

Treatment

Discussion

Personal opinion :There remains some diagnostic uncertainty regarding the exact nature of this lesion.

i feel that there's a degree of diagnostic dispute was considered between giant cell tumor of tendon sheath and other more bone invasive tumors.

Although the histopathological features are most consistent with a giant cell tumor of tendon sheath, the extensive bone lysis raised concern for a possible osteosarcomatous process, so as a doctor i had to have my own doubts and rejection for the report specially there was no phenotyping was done as CD68 or SATB2

Also because of the rarity of the case not much data found on such case , one article I've found that may be for a similar case with radial bone invasion

article attached below



A 9-year-old female Golden Retriever dog was presented with a firm swelling located over the right elbow joint. The owner reported that the mass had been gradually enlarging over several months, causing discomfort and lameness of the affected forelimb. There was no previous history of trauma or systemic illness.

On physical examination, a well-defined, firm, non-ulcerated mass was palpated over the right elbow region, .

The mass was non-movable, and did not show evidence of skin involvement. Range of motion in the elbow joint was severely reduced due to pain and local pressure from the mass.

No regional lymphadenopathy was detected, and the dog was otherwise bright and alert

CT screening show no any signs of metastasis in any other parts of the body

Examination of the submitted sample showed mesenchymal neoplastic formation that composed of polygonal to spindle-shaped cells mixed with multinucleated giant cells (Fig. 1). Multinucleated giant cells varied in number. The mononuclear cells had eosinophilic cytoplasm and distinct cell borders; their nuclei may vary in size, but mitoses are rare. The giant cells had more intensely staining cytoplasm; their multiple nuclei often have a wrinkled profile with little variation in size. The stroma appeared dense and collagenous.

Conclusion:
Giant cell tumor of tendon sheath

Surgical amputation of the forelimb was performed as the treatment of choice, ensuring removal of all visible tumor tissue with clean margins.

.

.

.

.

.

MERKEL CELL TUMOR

History

Clinical Presentation

Gross findings

Histopathology

Treatment

A 12-year-old female cat presented with a small swelling near the left eye and frontal bone region.


A firm, well-defined subcutaneous mass was noted without ulceration moderate painful exophthalmos . No systemic abnormalities were observed

A small, round, tan-white dermal to subcutaneous nodule, smooth and solid on cut surface, measuring about 2.5 cm.

Examination of the submitted sample revealed neoplasm formation in the dermal layer. The neoplastic cells form sheets in the dermis and subcutaneous tissue without epidermal or adnexal infiltration. The cells were round with hyperchromatic to vesicular nuclei and scant cytoplasm and distinct cell border. There were little nuclear or cellular pleomorphism and variable mitosis were observed (Fig. 1).

Conclusion:
Merkel cell tumor.

Phenotyping: CK20, chromogranin A and synaptophysin

Complete surgical excision of the mass was performed, including partial removal of the affected frontal bone and enucleation of the left eye due to tumor involvement of the periocular tissues.

.

.

.

.

.

.

.

.

.

.

TRICHOBLASTOMA

History

Clinical Presentation

Gross findings

Histopathology

Treatment

A 6-year-old male cat presented with a slowly growing mass on the right shoulder. the lesion appeared 2 months ago


The lesion was firm, well-circumscribed, non-ulcerated, and located within the dermis. The cat was otherwise healthy.


A single mass, tan to gray dermal mass measuring about 1 cm, elevating the overlying skin. The cut surface was smooth and solid


Microscopic examination of the submitted sample revealed multilobulated, dermal neoplasm (Fig. 1) elevates the epidermis with cystic degeneration anastomosing cords merge into islands of cells with markedly vacuolated cytoplasm.

Some cells arranged as ribbon, rosette or cords embedded in fibrous stroma; generally, two cells wide with surrounding fibrous stroma (Fig. 2). While others arranged in trabecular pattern characterized by presence of basaloid epithelial cells with prominent peripheral palisading and centrally located cells with more abundant cytoplasm. Neoplastic cells were polygonal and arranged on a loose fibrovascular stroma with evident mitotic figure

Complete surgical excision was performed. Prognosis is excellent, as trichoblastomas are benign and recurrence is uncommon.

.

.

.

.

.

MULTICENTRIC LYMPHOMA

History

Clinical Presentation

Histopathology

Treatment

Prognosis

Discussion

The patient presented with generalized lymphadenopathy, involving multiple peripheral lymph nodes.
The owner reported temporary blindness, which resolved following initiation of chemotherapy. No prior significant medical history was noted.

Multiple enlarged lymph nodes were palpated (cervical, axillary, and popliteal).

Mild lethargy and inappetence noted

Neurologic signs (temporary vision loss) were suspected to be secondary to CNS or ocular involvement by lymphoma, which improved post-treatment.

No other major systemic abnormalities were observed.

xamination of lymph node biopsy showed reactive small and intermediate mature lymphocytes with presence of mitotic figures (Fig. 1).

The neoplastic cells composed of round cells arranged in sheets on a pre-existing fibrovascular stroma.

Neoplastic cells had distinct cell borders, a moderate amount of eosinophilic, granular cytoplasm, a round nucleus that is approximately 1.5x larger than a red blood cell (intermediate size) with finely stippled chromatin and one variably prominent nucleolus. Anisocytosis and anisokaryosis were mild to moderate. There was rare single cell necrosis.

Phenotyping:
CD3 and CD79a

Immunophenotyping revealed expression of CD3 and CD79a, confirming the presence of both T- and B-cell populations, suggestive of a mixed-cell type lymphoma.

The patient was started on a CHOP-19 chemotherapy protocol (Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone).
Following treatment:

Vision returned within days of therapy initiation.Lymph node size reduced significantly after the first cycles size reduced (X-Ray) attached

The patient showed good tolerance and partial remission during the initial treatment phase

curruntly on week 9 of treatment ( Case will be updated



The patient was started on a CHOP-19 chemotherapy protocol (Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone).
Following treatment:

Vision returned within days of therapy initiation.Lymph node size reduced significantly after the first cycles size reduced The current case represents a high-stage (Stage Vb) multicentric lymphoma with evidence of systemic and possible CNS/ocular involvement. Such cases are classified as advanced-stage disease, typically carrying a guarded prognosis.


Despite the high stage, the dog demonstrated notable clinical improvement and resolution of blindness following initiation of CHOP-19 chemotherapy, confirming that the tumor remained chemoresponsive. Early response to treatment is one of the most reliable positive prognostic indicators, even in advanced disease



Canine multicentric lymphoma is among the most common hematopoietic malignancies, characterized by progressive lymphadenopathy and potential involvement of extra nodal organs, including the central nervous system (CNS) and eyes

In the present case, the histopathological and immunophenotypic findings confirmed an intermediate-grade lymphoma of mixed T- and B-cell origin, consistent with a moderately aggressive biological behavior


regarding prognosis

The CHOP-19 protocol (Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone) remains the gold standard for the treatment of canine multicentric lymphoma, offering the highest likelihood of inducing remission.

Expected response rate: Approximately 70-80% of dogs achieve partial or complete remission after induction therapy.

Median remission duration: 6–10 months for intermediate-grade lymphoma

Median survival time: Typically 10–14 months, though some cases may exceed 18 months with continued maintenance or rescue therapy.

.

.

.

.

.

.

TRANASIMISSIBLE VENERIAL TUMOR (TVT)

History

Gross findings

Histopathology

Treatment

An adult female dog presented with a history of massive vulvar swelling .


multinodular mass was observed protruding the vulva .

Sheets of round neoplastic cells with distinct cell borders, centrally placed round nuclei, coarse chromatin, and moderate vacuolated cytoplasm—findings consistent with transmissible venereal tumor (TVT).

The treatment of choice for TVT is chemotherapy, specifically with vincristine sulfate.

  • Drug: Vincristine sulfate
  • Dose: 0.025 mg/kg (or 0.5–0.7 mg/m²)
  • Route: Intravenous (slow IV injection)
  • Frequency: Once weekly
  • Duration: Typically 4–6 sessions, until complete regression of the tumor

.

.

..

.

LIPID-RICH CARCINOMA

History

Clinical Presentation

Gross findings

Histopathology

Treatment

An 8-year-old female dog presented with a progressively enlarging mass over the ventral abdomen noticed over several months.

A large, pendulous mass was observed, causing discomfort and reduced mobility. No systemic signs were noted initially.


A single, encapsulated, soft to firm, yellowish mass weighing 2.8 kg.


Tumor mass showed expanding the subcutis, infiltrating surrounding adipose and mammary tissue, and appeared unencapsulated multilobulated neoplasm composed of polygonal cells arranged in islands and trabeculae on a fine to moderate fibrovascular stroma. Neoplastic cells had distinct cell borders with moderate to abundant eosinophilic cytoplasm containing numerous small vacuoles or a single large discrete vacuole (lipid) that frequently peripheralized the nucleus (Fig. 1–2). Nuclei appeared round to oval with coarsely stippled chromatin and variably distinct nucleolus or flattened and hyperchromatic. Anisocytosis and anisokaryosis are moderate. Mitoses averages were commonly observed.

Scattered throughout the neoplasm were aggregates of lymphocytes, plasma cells, and fewer neutrophils, occasionally admixed with necrotic debris and areas of hemorrhage with few hemosiderin-laden macrophages.

Complete surgical excision of the mass was performed. Postoperative recovery was uneventful. The owner declined adjunctive chemotherapy. Follow-up at three months showed no recurrence or metastasis.

.

.

.

.

.

.

.

ANAPLASTIC CARCINOMA

History

Clinical Presentation

Gross findings

Histopathology

Treatment

A 14-year-old female cat was presented with a progressively enlarging mammary mass. The owner reported rapid tumor growth over a few weeks and reduced activity.

On physical examination, 2 firm, irregular, ulcerated mammary masses was noted, adherent to underlying tissues. No obvious respiratory distress or abdominal abnormalities were initially detected.


The excised mammary masses was firm, lobulated, and infiltrative, extending into adjacent subcutaneous tissues. The cut surface appeared grayish-white and fibrous, with areas of necrosis.


The mammary gland showed anaplastic carcinoma type that characterized by invasion of the neoplastic cells interlobular connective tissue with severe desmoplasia. Neoplastic cells were individualized or grouped in small nests; they were also round, oval, or polygonal and 15 to 70 µm in diameter, with moderate to abundant cytoplasm. Nuclei appeared large, round to oval with coarsely stippled chromatin. Anisokaryosis and anisocytosis were severe with bizarre karyomegalic nuclei, numerous giant cells and frequent atypical mitosis. The invading epithelial cells evoked a marked desmoplastic/scirrhous response with abundant fibroplasia. The stroma infiltrated with inflammatory cells (Fig. 1).

Surgical excision of the affected mammary gland (radical mastectomy) was performed to remove the primary tumor and surrounding tissues. Due to the highly infiltrative and aggressive nature of anaplastic carcinoma, wide surgical margins were ensured. Postoperative care included analgesics and antibiotics to prevent infection and support healing.

Given the high metastatic potential of this tumor type, adjuvant chemotherapy was recommended.

.

.

.

.

.

.

ADENOCARCINOMA

History

Clinical Presentation

Gross findings

Histopathology

Treatment

A 6-year-old female cat was presented with a progressively enlarging mass in the mammary region. The owner reported no history of contraceptive administration or previous reproductive disorders. The mass had been noticed 2 months earlier and showed continuous growth, with occasional discomfort and licking at the affected area.

on physical examination, a firm, irregular, multinodular and immovable mammary mass was detected in the right abdominal sider.

The overlying skin showed mild tension and focal ulceration. Regional lymph nodes were slightly enlarged and palpable.

No respiratory distress or systemic abnormalities were noted at the time of examination.

Surgical excision of the mass revealed a large, irregularly bordered tumor firmly adherent to the underlying abdominal musculature.

During dissection, infiltration of the abdominal muscle fibers by the tumor was evident, necessitating partial sacrifice of the involved muscle to achieve clear margins.
The excised mass measured14 x 6 centimeters in diameter, with a heterogeneous cut surface showing whitish to gray areas interspersed with hemorrhagic and necrotic zones.

Tumor mass composed of ductal epithelial cells that arranged in solid sheets and fusiform arrangement and arranged in clusters or large groups of cells with numerous detected mitosis (Fig. 1). The neoplastic mammary tissue was multifocal infiltrated with variable number of mononuclear inflammatory cells.

The epithelium showed increased nuclear and cellular pleomorphism and variable numbers of mitoses and variable nuclear morphology. The neoplastic cells showed metastatic through the blood and lymph vessels (Fig. 2). The dermal layer showed severe extensive hemorrhages associated with existence of hemosiderin pigment (Fig. 3).

Conclusion:
Mammary adenocarcinoma with vascular and lymphatic invasion.

A radical surgical excision was performed, including removal of the affected mammary gland and partial resection of the invaded abdominal muscle to ensure clean margins. Postoperative management included:

Broad-spectrum antibiotics to prevent secondary infection.

Analgesic and anti-inflammatory therapy for pain control.

Regular wound care and monitoring for healing and recurrence.

Follow-up recommendations:

Abdominal ultrasound and thoracic radiography to monitor for metastatic spread.

Consideration of adjunctive chemotherapy depending on staging results and postoperative findings.

Regular re-evaluation every 2–3 months.

.

.

.

.

.

.

.

.

.

.

TRANASIMISSIBLE VENERIAL TUMOR (TVT)

History

Clinical Presentation

Gross findings

Histopathology

Treatment

A 4-year-old intact male mixed-breed dog was presented with a history of a progressively enlarging mass on the penis over the past month. The owner also reported occasional bleeding from the prepuce and excessive licking of the genital area. The dog had a history of roaming and mating with stray females.


Abdominal ultrasonographic examination revealed atrophic hepatic parenchyma adjacent to the cyst with regular boundaries and heterogeneous echogenicity and multiple (2) anechoic cystic masses that occupied nearly half of the abdomen: one near the caudate lobe

Physical examination revealed a friable, cauliflower-like, reddish mass protruding from the penile mucosa, approximately 3 cm in diameter. Mild serosanguinous discharge was observed. No lymphadenopathy or systemic signs were noted.


Fine-needle aspiration and cytological examination showed round cells with distinct borders, moderate pale cytoplasm containing clear vacuoles, and centrally placed round nuclei — consistent with Transmissible Venereal Tumor (TVT). Routine hematology and biochemistry were within normal limits.


The dog was treated with vincristine sulfate at a dose of 0.025 mg/kg intravenously once weekly for six weeks. The mass regressed progressively, with complete remission observed by the fifth treatment. No adverse drug reactions were noted.

.

.

.

.

.

© All Rights Reserved